diff --git a/Classification/XGBoost/src/main/java/org/tribuo/classification/xgboost/XGBoostClassificationConverter.java b/Classification/XGBoost/src/main/java/org/tribuo/classification/xgboost/XGBoostClassificationConverter.java
index 1abc94786..597c0aa60 100644
--- a/Classification/XGBoost/src/main/java/org/tribuo/classification/xgboost/XGBoostClassificationConverter.java
+++ b/Classification/XGBoost/src/main/java/org/tribuo/classification/xgboost/XGBoostClassificationConverter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,16 @@
 
 package org.tribuo.classification.xgboost;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
 import org.tribuo.Example;
 import org.tribuo.ImmutableOutputInfo;
 import org.tribuo.Prediction;
 import org.tribuo.classification.Label;
 import org.tribuo.common.xgboost.XGBoostOutputConverter;
+import org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto;
+import org.tribuo.protos.ProtoSerializableClass;
+import org.tribuo.protos.ProtoUtil;
 
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
@@ -29,14 +34,36 @@
 /**
  * Converts XGBoost outputs into {@link Label} {@link Prediction}s.
  */
+@ProtoSerializableClass(version = XGBoostClassificationConverter.CURRENT_VERSION)
 public final class XGBoostClassificationConverter implements XGBoostOutputConverter<Label> {
     private static final long serialVersionUID = 1L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     /**
      * Constructs an XGBoostClassificationConverter.
      */
     public XGBoostClassificationConverter() {}
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    public static XGBoostClassificationConverter deserializeFromProto(int version, String className, Any message) {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        if (message.getValue() != ByteString.EMPTY) {
+            throw new IllegalArgumentException("Invalid proto");
+        }
+        return new XGBoostClassificationConverter();
+    }
+
     @Override
     public boolean generatesProbabilities() {
         return true;
@@ -92,4 +119,14 @@ public List<Prediction<Label>> convertBatchOutput(ImmutableOutputInfo<Label> inf
 
         return predictions;
     }
+
+    @Override
+    public XGBoostOutputConverterProto serialize() {
+        return ProtoUtil.serialize(this);
+    }
+
+    @Override
+    public Class<Label> getTypeWitness() {
+        return Label.class;
+    }
 }
diff --git a/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoost.java b/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoost.java
index e837981fa..d4d532488 100644
--- a/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoost.java
+++ b/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoost.java
@@ -221,6 +221,7 @@ public void testDenseData() {
         Pair<Dataset<Label>,Dataset<Label>> p = LabelledDataGenerator.denseTrainTest();
         Model<Label> model = testXGBoost(t,p);
         Helpers.testModelSerialization(model,Label.class);
+        Helpers.testModelProtoSerialization(model, Label.class, p.getB());
         testXGBoost(dart,p);
         testXGBoost(linear,p);
         XGBoostModel<Label> m = testXGBoost(gbtree,p);
diff --git a/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoostExternalModel.java b/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoostExternalModel.java
index 3437a81e6..30131343f 100644
--- a/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoostExternalModel.java
+++ b/Classification/XGBoost/src/test/java/org/tribuo/classification/xgboost/TestXGBoostExternalModel.java
@@ -67,6 +67,7 @@ public void testMNIST() throws IOException, URISyntaxException {
         assertEquals(0.0, evaluation.balancedErrorRate(), 1e-6);
 
         Helpers.testModelSerialization(transposedMNISTXGB,Label.class);
+        Helpers.testModelProtoSerialization(transposedMNISTXGB, Label.class, transposedMNIST);
     }
 
     @Test
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostExternalModel.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostExternalModel.java
index e278c349a..d0ca3851a 100644
--- a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostExternalModel.java
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostExternalModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,13 @@
 
 package org.tribuo.common.xgboost;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
 import com.oracle.labs.mlrg.olcut.provenance.Provenance;
 import com.oracle.labs.mlrg.olcut.util.Pair;
+import java.util.Arrays;
+import java.util.stream.Collectors;
 import ml.dmlc.xgboost4j.java.Booster;
 import ml.dmlc.xgboost4j.java.DMatrix;
 import ml.dmlc.xgboost4j.java.XGBoost;
@@ -29,12 +34,17 @@
 import org.tribuo.Output;
 import org.tribuo.OutputFactory;
 import org.tribuo.Prediction;
+import org.tribuo.common.xgboost.protos.XGBoostExternalModelProto;
+import org.tribuo.impl.ModelDataCarrier;
 import org.tribuo.interop.ExternalDatasetProvenance;
 import org.tribuo.interop.ExternalModel;
 import org.tribuo.interop.ExternalTrainerProvenance;
 import org.tribuo.math.la.SparseVector;
+import org.tribuo.protos.ProtoUtil;
+import org.tribuo.protos.core.ModelProto;
 import org.tribuo.provenance.DatasetProvenance;
 import org.tribuo.provenance.ModelProvenance;
+import org.tribuo.util.Util;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
@@ -89,6 +99,11 @@ public final class XGBoostExternalModel<T extends Output<T>> extends ExternalMod
 
     private static final Logger logger = Logger.getLogger(XGBoostExternalModel.class.getName());
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final XGBoostOutputConverter<T> converter;
 
     /**
@@ -115,6 +130,37 @@ private XGBoostExternalModel(String name, ModelProvenance provenance,
         this.converter = converter;
     }
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    @SuppressWarnings({"unchecked","rawtypes"}) // output converter and domain are checked via getClass.
+    public static XGBoostExternalModel<?> deserializeFromProto(int version, String className, Any message) throws InvalidProtocolBufferException, XGBoostError, IOException {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        XGBoostExternalModelProto proto = message.unpack(XGBoostExternalModelProto.class);
+
+        XGBoostOutputConverter<?> converter = ProtoUtil.deserialize(proto.getConverter());
+        Class<?> converterWitness = converter.getTypeWitness();
+        ModelDataCarrier<?> carrier = ModelDataCarrier.deserialize(proto.getMetadata());
+        if (!carrier.outputDomain().getOutput(0).getClass().equals(converterWitness)) {
+            throw new IllegalStateException("Invalid protobuf, output domain does not match the converter, found " + carrier.outputDomain().getClass() + " and " + converterWitness);
+        }
+        int[] featureForwardMapping = Util.toPrimitiveInt(proto.getForwardFeatureMappingList());
+        int[] featureBackwardMapping = Util.toPrimitiveInt(proto.getBackwardFeatureMappingList());
+        if (!validateFeatureMapping(featureForwardMapping,featureBackwardMapping,carrier.featureDomain())) {
+            throw new IllegalStateException("Invalid protobuf, external<->Tribuo feature mapping does not form a bijection");
+        }
+
+        Booster model = XGBoost.loadModel(proto.getModel().toByteArray());
+
+        return new XGBoostExternalModel(carrier.name(), carrier.provenance(), carrier.featureDomain(),
+                carrier.outputDomain(), featureForwardMapping, featureBackwardMapping, model, converter);
+    }
+
     @Override
     protected DMatrix convertFeatures(SparseVector input) {
         try {
@@ -201,6 +247,30 @@ public Map<String, List<Pair<String, Double>>> getTopFeatures(int n) {
         }
     }
 
+    @Override
+    public ModelProto serialize() {
+        ModelDataCarrier<T> carrier = createDataCarrier();
+
+        XGBoostExternalModelProto.Builder modelBuilder = XGBoostExternalModelProto.newBuilder();
+        modelBuilder.setMetadata(carrier.serialize());
+        modelBuilder.setConverter(converter.serialize());
+        modelBuilder.addAllForwardFeatureMapping(Arrays.stream(featureForwardMapping).boxed().collect(
+            Collectors.toList()));
+        modelBuilder.addAllBackwardFeatureMapping(Arrays.stream(featureBackwardMapping).boxed().collect(Collectors.toList()));
+        try {
+            modelBuilder.setModel(ByteString.copyFrom(model.toByteArray()));
+        } catch (XGBoostError e) {
+            throw new IllegalStateException("Failed to serialize XGBoost model");
+        }
+
+        ModelProto.Builder builder = ModelProto.newBuilder();
+        builder.setSerializedData(Any.pack(modelBuilder.build()));
+        builder.setClassName(XGBoostExternalModel.class.getName());
+        builder.setVersion(CURRENT_VERSION);
+
+        return builder.build();
+    }
+
     @Override
     protected XGBoostExternalModel<T> copy(String newName, ModelProvenance newProvenance) {
         return new XGBoostExternalModel<>(newName, newProvenance, featureIDMap, outputIDInfo,
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostModel.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostModel.java
index c8f8ee55a..e5bc1d2fd 100644
--- a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostModel.java
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,9 @@
 
 package org.tribuo.common.xgboost;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
 import com.oracle.labs.mlrg.olcut.util.MutableDouble;
 import com.oracle.labs.mlrg.olcut.util.Pair;
 import ml.dmlc.xgboost4j.java.Booster;
@@ -30,6 +33,10 @@
 import org.tribuo.Output;
 import org.tribuo.Prediction;
 import org.tribuo.common.xgboost.XGBoostTrainer.DMatrixTuple;
+import org.tribuo.common.xgboost.protos.XGBoostModelProto;
+import org.tribuo.impl.ModelDataCarrier;
+import org.tribuo.protos.ProtoUtil;
+import org.tribuo.protos.core.ModelProto;
 import org.tribuo.provenance.ModelProvenance;
 import org.tribuo.provenance.TrainerProvenance;
 
@@ -81,6 +88,11 @@ public final class XGBoostModel<T extends Output<T>> extends Model<T> {
 
     private static final Logger logger = Logger.getLogger(XGBoostModel.class.getName());
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final XGBoostOutputConverter<T> converter;
 
     // Used to signal if the model has been rewritten to fix the issue with multidimensional XGBoost regression models in 4.0 and 4.1.0.
@@ -100,6 +112,35 @@ public final class XGBoostModel<T extends Output<T>> extends Model<T> {
         this.regression41MappingFix = true;
     }
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    public static XGBoostModel<?> deserializeFromProto(int version, String className, Any message) throws InvalidProtocolBufferException, XGBoostError, IOException {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        XGBoostModelProto proto = message.unpack(XGBoostModelProto.class);
+
+        XGBoostOutputConverter<?> converter = ProtoUtil.deserialize(proto.getConverter());
+        Class<?> converterWitness = converter.getTypeWitness();
+        ModelDataCarrier<?> carrier = ModelDataCarrier.deserialize(proto.getMetadata());
+        if (!carrier.outputDomain().getOutput(0).getClass().equals(converterWitness)) {
+            throw new IllegalStateException("Invalid protobuf, output domain does not match the converter, found " + carrier.outputDomain().getClass() + " and " + converterWitness);
+        }
+        List<Booster> models = new ArrayList<>();
+        for (ByteString b : proto.getModelsList()) {
+            models.add(XGBoost.loadModel(b.toByteArray()));
+        }
+        if (models.isEmpty()) {
+            throw new IllegalStateException("Invalid protobuf, no XGBoost models were found");
+        }
+
+        return new XGBoostModel(carrier.name(),carrier.provenance(),carrier.featureDomain(),carrier.outputDomain(),models,converter);
+    }
+
     /**
      * Returns an unmodifiable list containing a copy of each model.
      * <p>
@@ -292,6 +333,29 @@ protected Model<T> copy(String newName, ModelProvenance newProvenance) {
         return new XGBoostModel<>(newName, newProvenance, featureIDMap, outputIDInfo, newModels, converter);
     }
 
+    @Override
+    public ModelProto serialize() {
+        ModelDataCarrier<T> carrier = createDataCarrier();
+
+        XGBoostModelProto.Builder modelBuilder = XGBoostModelProto.newBuilder();
+        modelBuilder.setMetadata(carrier.serialize());
+        modelBuilder.setConverter(converter.serialize());
+        try {
+            for (Booster b : models) {
+                modelBuilder.addModels(ByteString.copyFrom(b.toByteArray()));
+            }
+        } catch (XGBoostError e) {
+            throw new IllegalStateException("Failed to serialize XGBoost model");
+        }
+
+        ModelProto.Builder builder = ModelProto.newBuilder();
+        builder.setSerializedData(Any.pack(modelBuilder.build()));
+        builder.setClassName(XGBoostModel.class.getName());
+        builder.setVersion(CURRENT_VERSION);
+
+        return builder.build();
+    }
+
     private void writeObject(ObjectOutputStream out) throws IOException {
         out.defaultWriteObject();
         try {
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostOutputConverter.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostOutputConverter.java
index 67a9c316c..309a19d9e 100644
--- a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostOutputConverter.java
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/XGBoostOutputConverter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,11 +23,14 @@
 
 import java.io.Serializable;
 import java.util.List;
+import org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto;
+import org.tribuo.protos.ProtoSerializable;
 
 /**
  * Converts the output of XGBoost into the appropriate prediction type.
  */
-public interface XGBoostOutputConverter<T extends Output<T>> extends Serializable {
+public interface XGBoostOutputConverter<T extends Output<T>> extends
+    ProtoSerializable<XGBoostOutputConverterProto>, Serializable {
 
     /**
      * Does this converter produce probabilities?
@@ -55,4 +58,15 @@ public interface XGBoostOutputConverter<T extends Output<T>> extends Serializabl
      */
     public List<Prediction<T>> convertBatchOutput(ImmutableOutputInfo<T> info, List<float[][]> probabilities, int[] numValidFeatures, Example<T>[] examples);
 
+    /**
+     * Gets the type witness for the output this converter uses.
+     * <p>
+     * The default implementation throws {@link UnsupportedOperationException} for compatibility
+     * with subclasses which don't support protobuf serialization.
+     * @return The class of the output.
+     */
+    default public Class<T> getTypeWitness() {
+        throw new UnsupportedOperationException("This class has not been updated to support protobuf serialization.");
+    }
+
 }
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/TribuoXgboost.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/TribuoXgboost.java
new file mode 100644
index 000000000..9c4b199fa
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/TribuoXgboost.java
@@ -0,0 +1,87 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+public final class TribuoXgboost {
+  private TribuoXgboost() {}
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistryLite registry) {
+  }
+
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistry registry) {
+    registerAllExtensions(
+        (com.google.protobuf.ExtensionRegistryLite) registry);
+  }
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_xgboost_XGBoostModelProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_fieldAccessorTable;
+
+  public static com.google.protobuf.Descriptors.FileDescriptor
+      getDescriptor() {
+    return descriptor;
+  }
+  private static  com.google.protobuf.Descriptors.FileDescriptor
+      descriptor;
+  static {
+    java.lang.String[] descriptorData = {
+      "\n\024tribuo-xgboost.proto\022\025tribuo.common.xg" +
+      "boost\032\031google/protobuf/any.proto\032\021tribuo" +
+      "-core.proto\"q\n\033XGBoostOutputConverterPro" +
+      "to\022\017\n\007version\030\001 \001(\005\022\022\n\nclass_name\030\002 \001(\t\022" +
+      "-\n\017serialized_data\030\003 \001(\0132\024.google.protob" +
+      "uf.Any\"\231\001\n\021XGBoostModelProto\022-\n\010metadata" +
+      "\030\001 \001(\0132\033.tribuo.core.ModelDataProto\022E\n\tc" +
+      "onverter\030\002 \001(\01322.tribuo.common.xgboost.X" +
+      "GBoostOutputConverterProto\022\016\n\006models\030\003 \003" +
+      "(\014\"\343\001\n\031XGBoostExternalModelProto\022-\n\010meta" +
+      "data\030\001 \001(\0132\033.tribuo.core.ModelDataProto\022" +
+      "E\n\tconverter\030\002 \001(\01322.tribuo.common.xgboo" +
+      "st.XGBoostOutputConverterProto\022\r\n\005model\030" +
+      "\003 \001(\014\022\037\n\027forward_feature_mapping\030\004 \003(\005\022 " +
+      "\n\030backward_feature_mapping\030\005 \003(\005B$\n org." +
+      "tribuo.common.xgboost.protosP\001b\006proto3"
+    };
+    descriptor = com.google.protobuf.Descriptors.FileDescriptor
+      .internalBuildGeneratedFileFrom(descriptorData,
+        new com.google.protobuf.Descriptors.FileDescriptor[] {
+          com.google.protobuf.AnyProto.getDescriptor(),
+          org.tribuo.protos.core.TribuoCore.getDescriptor(),
+        });
+    internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor =
+      getDescriptor().getMessageTypes().get(0);
+    internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor,
+        new java.lang.String[] { "Version", "ClassName", "SerializedData", });
+    internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor =
+      getDescriptor().getMessageTypes().get(1);
+    internal_static_tribuo_common_xgboost_XGBoostModelProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor,
+        new java.lang.String[] { "Metadata", "Converter", "Models", });
+    internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor =
+      getDescriptor().getMessageTypes().get(2);
+    internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor,
+        new java.lang.String[] { "Metadata", "Converter", "Model", "ForwardFeatureMapping", "BackwardFeatureMapping", });
+    com.google.protobuf.AnyProto.getDescriptor();
+    org.tribuo.protos.core.TribuoCore.getDescriptor();
+  }
+
+  // @@protoc_insertion_point(outer_class_scope)
+}
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProto.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProto.java
new file mode 100644
index 000000000..e4b9e8508
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProto.java
@@ -0,0 +1,1227 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+/**
+ * <pre>
+ *XGBoostExternalModel proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.xgboost.XGBoostExternalModelProto}
+ */
+public final class XGBoostExternalModelProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.xgboost.XGBoostExternalModelProto)
+    XGBoostExternalModelProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use XGBoostExternalModelProto.newBuilder() to construct.
+  private XGBoostExternalModelProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private XGBoostExternalModelProto() {
+    model_ = com.google.protobuf.ByteString.EMPTY;
+    forwardFeatureMapping_ = emptyIntList();
+    backwardFeatureMapping_ = emptyIntList();
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new XGBoostExternalModelProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private XGBoostExternalModelProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
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+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 10: {
+            org.tribuo.protos.core.ModelDataProto.Builder subBuilder = null;
+            if (metadata_ != null) {
+              subBuilder = metadata_.toBuilder();
+            }
+            metadata_ = input.readMessage(org.tribuo.protos.core.ModelDataProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(metadata_);
+              metadata_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 18: {
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder subBuilder = null;
+            if (converter_ != null) {
+              subBuilder = converter_.toBuilder();
+            }
+            converter_ = input.readMessage(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(converter_);
+              converter_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 26: {
+
+            model_ = input.readBytes();
+            break;
+          }
+          case 32: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              forwardFeatureMapping_ = newIntList();
+              mutable_bitField0_ |= 0x00000001;
+            }
+            forwardFeatureMapping_.addInt(input.readInt32());
+            break;
+          }
+          case 34: {
+            int length = input.readRawVarint32();
+            int limit = input.pushLimit(length);
+            if (!((mutable_bitField0_ & 0x00000001) != 0) && input.getBytesUntilLimit() > 0) {
+              forwardFeatureMapping_ = newIntList();
+              mutable_bitField0_ |= 0x00000001;
+            }
+            while (input.getBytesUntilLimit() > 0) {
+              forwardFeatureMapping_.addInt(input.readInt32());
+            }
+            input.popLimit(limit);
+            break;
+          }
+          case 40: {
+            if (!((mutable_bitField0_ & 0x00000002) != 0)) {
+              backwardFeatureMapping_ = newIntList();
+              mutable_bitField0_ |= 0x00000002;
+            }
+            backwardFeatureMapping_.addInt(input.readInt32());
+            break;
+          }
+          case 42: {
+            int length = input.readRawVarint32();
+            int limit = input.pushLimit(length);
+            if (!((mutable_bitField0_ & 0x00000002) != 0) && input.getBytesUntilLimit() > 0) {
+              backwardFeatureMapping_ = newIntList();
+              mutable_bitField0_ |= 0x00000002;
+            }
+            while (input.getBytesUntilLimit() > 0) {
+              backwardFeatureMapping_.addInt(input.readInt32());
+            }
+            input.popLimit(limit);
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      if (((mutable_bitField0_ & 0x00000001) != 0)) {
+        forwardFeatureMapping_.makeImmutable(); // C
+      }
+      if (((mutable_bitField0_ & 0x00000002) != 0)) {
+        backwardFeatureMapping_.makeImmutable(); // C
+      }
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.class, org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.Builder.class);
+  }
+
+  public static final int METADATA_FIELD_NUMBER = 1;
+  private org.tribuo.protos.core.ModelDataProto metadata_;
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  @java.lang.Override
+  public boolean hasMetadata() {
+    return metadata_ != null;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProto getMetadata() {
+    return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+    return getMetadata();
+  }
+
+  public static final int CONVERTER_FIELD_NUMBER = 2;
+  private org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto converter_;
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return Whether the converter field is set.
+   */
+  @java.lang.Override
+  public boolean hasConverter() {
+    return converter_ != null;
+  }
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return The converter.
+   */
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter() {
+    return converter_ == null ? org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+  }
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder() {
+    return getConverter();
+  }
+
+  public static final int MODEL_FIELD_NUMBER = 3;
+  private com.google.protobuf.ByteString model_;
+  /**
+   * <code>bytes model = 3;</code>
+   * @return The model.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString getModel() {
+    return model_;
+  }
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+  public static final int FORWARD_FEATURE_MAPPING_FIELD_NUMBER = 4;
+  private com.google.protobuf.Internal.IntList forwardFeatureMapping_;
+  /**
+   * <code>repeated int32 forward_feature_mapping = 4;</code>
+   * @return A list containing the forwardFeatureMapping.
+   */
+  @java.lang.Override
+  public java.util.List<java.lang.Integer>
+      getForwardFeatureMappingList() {
+    return forwardFeatureMapping_;
+  }
+  /**
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+   * @return The count of forwardFeatureMapping.
+   */
+  public int getForwardFeatureMappingCount() {
+    return forwardFeatureMapping_.size();
+  }
+  /**
+   * <code>repeated int32 forward_feature_mapping = 4;</code>
+   * @param index The index of the element to return.
+   * @return The forwardFeatureMapping at the given index.
+   */
+  public int getForwardFeatureMapping(int index) {
+    return forwardFeatureMapping_.getInt(index);
+  }
+  private int forwardFeatureMappingMemoizedSerializedSize = -1;
+
+  public static final int BACKWARD_FEATURE_MAPPING_FIELD_NUMBER = 5;
+  private com.google.protobuf.Internal.IntList backwardFeatureMapping_;
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @return A list containing the backwardFeatureMapping.
+   */
+  @java.lang.Override
+  public java.util.List<java.lang.Integer>
+      getBackwardFeatureMappingList() {
+    return backwardFeatureMapping_;
+  }
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @return The count of backwardFeatureMapping.
+   */
+  public int getBackwardFeatureMappingCount() {
+    return backwardFeatureMapping_.size();
+  }
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @param index The index of the element to return.
+   * @return The backwardFeatureMapping at the given index.
+   */
+  public int getBackwardFeatureMapping(int index) {
+    return backwardFeatureMapping_.getInt(index);
+  }
+  private int backwardFeatureMappingMemoizedSerializedSize = -1;
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
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+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    getSerializedSize();
+    if (metadata_ != null) {
+      output.writeMessage(1, getMetadata());
+    }
+    if (converter_ != null) {
+      output.writeMessage(2, getConverter());
+    }
+    if (!model_.isEmpty()) {
+      output.writeBytes(3, model_);
+    }
+    if (getForwardFeatureMappingList().size() > 0) {
+      output.writeUInt32NoTag(34);
+      output.writeUInt32NoTag(forwardFeatureMappingMemoizedSerializedSize);
+    }
+    for (int i = 0; i < forwardFeatureMapping_.size(); i++) {
+      output.writeInt32NoTag(forwardFeatureMapping_.getInt(i));
+    }
+    if (getBackwardFeatureMappingList().size() > 0) {
+      output.writeUInt32NoTag(42);
+      output.writeUInt32NoTag(backwardFeatureMappingMemoizedSerializedSize);
+    }
+    for (int i = 0; i < backwardFeatureMapping_.size(); i++) {
+      output.writeInt32NoTag(backwardFeatureMapping_.getInt(i));
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (metadata_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(1, getMetadata());
+    }
+    if (converter_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(2, getConverter());
+    }
+    if (!model_.isEmpty()) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeBytesSize(3, model_);
+    }
+    {
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+      for (int i = 0; i < forwardFeatureMapping_.size(); i++) {
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+          .computeInt32SizeNoTag(forwardFeatureMapping_.getInt(i));
+      }
+      size += dataSize;
+      if (!getForwardFeatureMappingList().isEmpty()) {
+        size += 1;
+        size += com.google.protobuf.CodedOutputStream
+            .computeInt32SizeNoTag(dataSize);
+      }
+      forwardFeatureMappingMemoizedSerializedSize = dataSize;
+    }
+    {
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+      for (int i = 0; i < backwardFeatureMapping_.size(); i++) {
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+          .computeInt32SizeNoTag(backwardFeatureMapping_.getInt(i));
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+      size += dataSize;
+      if (!getBackwardFeatureMappingList().isEmpty()) {
+        size += 1;
+        size += com.google.protobuf.CodedOutputStream
+            .computeInt32SizeNoTag(dataSize);
+      }
+      backwardFeatureMappingMemoizedSerializedSize = dataSize;
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.xgboost.protos.XGBoostExternalModelProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.xgboost.protos.XGBoostExternalModelProto other = (org.tribuo.common.xgboost.protos.XGBoostExternalModelProto) obj;
+
+    if (hasMetadata() != other.hasMetadata()) return false;
+    if (hasMetadata()) {
+      if (!getMetadata()
+          .equals(other.getMetadata())) return false;
+    }
+    if (hasConverter() != other.hasConverter()) return false;
+    if (hasConverter()) {
+      if (!getConverter()
+          .equals(other.getConverter())) return false;
+    }
+    if (!getModel()
+        .equals(other.getModel())) return false;
+    if (!getForwardFeatureMappingList()
+        .equals(other.getForwardFeatureMappingList())) return false;
+    if (!getBackwardFeatureMappingList()
+        .equals(other.getBackwardFeatureMappingList())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    if (hasMetadata()) {
+      hash = (37 * hash) + METADATA_FIELD_NUMBER;
+      hash = (53 * hash) + getMetadata().hashCode();
+    }
+    if (hasConverter()) {
+      hash = (37 * hash) + CONVERTER_FIELD_NUMBER;
+      hash = (53 * hash) + getConverter().hashCode();
+    }
+    hash = (37 * hash) + MODEL_FIELD_NUMBER;
+    hash = (53 * hash) + getModel().hashCode();
+    if (getForwardFeatureMappingCount() > 0) {
+      hash = (37 * hash) + FORWARD_FEATURE_MAPPING_FIELD_NUMBER;
+      hash = (53 * hash) + getForwardFeatureMappingList().hashCode();
+    }
+    if (getBackwardFeatureMappingCount() > 0) {
+      hash = (37 * hash) + BACKWARD_FEATURE_MAPPING_FIELD_NUMBER;
+      hash = (53 * hash) + getBackwardFeatureMappingList().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.xgboost.protos.XGBoostExternalModelProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *XGBoostExternalModel proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.xgboost.XGBoostExternalModelProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.xgboost.XGBoostExternalModelProto)
+      org.tribuo.common.xgboost.protos.XGBoostExternalModelProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.class, org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+      if (converterBuilder_ == null) {
+        converter_ = null;
+      } else {
+        converter_ = null;
+        converterBuilder_ = null;
+      }
+      model_ = com.google.protobuf.ByteString.EMPTY;
+
+      forwardFeatureMapping_ = emptyIntList();
+      bitField0_ = (bitField0_ & ~0x00000001);
+      backwardFeatureMapping_ = emptyIntList();
+      bitField0_ = (bitField0_ & ~0x00000002);
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostExternalModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostExternalModelProto getDefaultInstanceForType() {
+      return org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostExternalModelProto build() {
+      org.tribuo.common.xgboost.protos.XGBoostExternalModelProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostExternalModelProto buildPartial() {
+      org.tribuo.common.xgboost.protos.XGBoostExternalModelProto result = new org.tribuo.common.xgboost.protos.XGBoostExternalModelProto(this);
+      int from_bitField0_ = bitField0_;
+      if (metadataBuilder_ == null) {
+        result.metadata_ = metadata_;
+      } else {
+        result.metadata_ = metadataBuilder_.build();
+      }
+      if (converterBuilder_ == null) {
+        result.converter_ = converter_;
+      } else {
+        result.converter_ = converterBuilder_.build();
+      }
+      result.model_ = model_;
+      if (((bitField0_ & 0x00000001) != 0)) {
+        forwardFeatureMapping_.makeImmutable();
+        bitField0_ = (bitField0_ & ~0x00000001);
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+      result.forwardFeatureMapping_ = forwardFeatureMapping_;
+      if (((bitField0_ & 0x00000002) != 0)) {
+        backwardFeatureMapping_.makeImmutable();
+        bitField0_ = (bitField0_ & ~0x00000002);
+      }
+      result.backwardFeatureMapping_ = backwardFeatureMapping_;
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.xgboost.protos.XGBoostExternalModelProto) {
+        return mergeFrom((org.tribuo.common.xgboost.protos.XGBoostExternalModelProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.xgboost.protos.XGBoostExternalModelProto other) {
+      if (other == org.tribuo.common.xgboost.protos.XGBoostExternalModelProto.getDefaultInstance()) return this;
+      if (other.hasMetadata()) {
+        mergeMetadata(other.getMetadata());
+      }
+      if (other.hasConverter()) {
+        mergeConverter(other.getConverter());
+      }
+      if (other.getModel() != com.google.protobuf.ByteString.EMPTY) {
+        setModel(other.getModel());
+      }
+      if (!other.forwardFeatureMapping_.isEmpty()) {
+        if (forwardFeatureMapping_.isEmpty()) {
+          forwardFeatureMapping_ = other.forwardFeatureMapping_;
+          bitField0_ = (bitField0_ & ~0x00000001);
+        } else {
+          ensureForwardFeatureMappingIsMutable();
+          forwardFeatureMapping_.addAll(other.forwardFeatureMapping_);
+        }
+        onChanged();
+      }
+      if (!other.backwardFeatureMapping_.isEmpty()) {
+        if (backwardFeatureMapping_.isEmpty()) {
+          backwardFeatureMapping_ = other.backwardFeatureMapping_;
+          bitField0_ = (bitField0_ & ~0x00000002);
+        } else {
+          ensureBackwardFeatureMappingIsMutable();
+          backwardFeatureMapping_.addAll(other.backwardFeatureMapping_);
+        }
+        onChanged();
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.xgboost.protos.XGBoostExternalModelProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.xgboost.protos.XGBoostExternalModelProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private org.tribuo.protos.core.ModelDataProto metadata_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> metadataBuilder_;
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return Whether the metadata field is set.
+     */
+    public boolean hasMetadata() {
+      return metadataBuilder_ != null || metadata_ != null;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return The metadata.
+     */
+    public org.tribuo.protos.core.ModelDataProto getMetadata() {
+      if (metadataBuilder_ == null) {
+        return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      } else {
+        return metadataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        metadata_ = value;
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(
+        org.tribuo.protos.core.ModelDataProto.Builder builderForValue) {
+      if (metadataBuilder_ == null) {
+        metadata_ = builderForValue.build();
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder mergeMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (metadata_ != null) {
+          metadata_ =
+            org.tribuo.protos.core.ModelDataProto.newBuilder(metadata_).mergeFrom(value).buildPartial();
+        } else {
+          metadata_ = value;
+        }
+        onChanged();
+      } else {
+        metadataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder clearMetadata() {
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+        onChanged();
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProto.Builder getMetadataBuilder() {
+      
+      onChanged();
+      return getMetadataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+      if (metadataBuilder_ != null) {
+        return metadataBuilder_.getMessageOrBuilder();
+      } else {
+        return metadata_ == null ?
+            org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> 
+        getMetadataFieldBuilder() {
+      if (metadataBuilder_ == null) {
+        metadataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder>(
+                getMetadata(),
+                getParentForChildren(),
+                isClean());
+        metadata_ = null;
+      }
+      return metadataBuilder_;
+    }
+
+    private org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto converter_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder> converterBuilder_;
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     * @return Whether the converter field is set.
+     */
+    public boolean hasConverter() {
+      return converterBuilder_ != null || converter_ != null;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     * @return The converter.
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter() {
+      if (converterBuilder_ == null) {
+        return converter_ == null ? org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+      } else {
+        return converterBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder setConverter(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto value) {
+      if (converterBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        converter_ = value;
+        onChanged();
+      } else {
+        converterBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder setConverter(
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder builderForValue) {
+      if (converterBuilder_ == null) {
+        converter_ = builderForValue.build();
+        onChanged();
+      } else {
+        converterBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder mergeConverter(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto value) {
+      if (converterBuilder_ == null) {
+        if (converter_ != null) {
+          converter_ =
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.newBuilder(converter_).mergeFrom(value).buildPartial();
+        } else {
+          converter_ = value;
+        }
+        onChanged();
+      } else {
+        converterBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder clearConverter() {
+      if (converterBuilder_ == null) {
+        converter_ = null;
+        onChanged();
+      } else {
+        converter_ = null;
+        converterBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder getConverterBuilder() {
+      
+      onChanged();
+      return getConverterFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder() {
+      if (converterBuilder_ != null) {
+        return converterBuilder_.getMessageOrBuilder();
+      } else {
+        return converter_ == null ?
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+      }
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder> 
+        getConverterFieldBuilder() {
+      if (converterBuilder_ == null) {
+        converterBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder>(
+                getConverter(),
+                getParentForChildren(),
+                isClean());
+        converter_ = null;
+      }
+      return converterBuilder_;
+    }
+
+    private com.google.protobuf.ByteString model_ = com.google.protobuf.ByteString.EMPTY;
+    /**
+     * <code>bytes model = 3;</code>
+     * @return The model.
+     */
+    @java.lang.Override
+    public com.google.protobuf.ByteString getModel() {
+      return model_;
+    }
+    /**
+     * <code>bytes model = 3;</code>
+     * @param value The model to set.
+     * @return This builder for chaining.
+     */
+    public Builder setModel(com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  
+      model_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>bytes model = 3;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearModel() {
+      
+      model_ = getDefaultInstance().getModel();
+      onChanged();
+      return this;
+    }
+
+    private com.google.protobuf.Internal.IntList forwardFeatureMapping_ = emptyIntList();
+    private void ensureForwardFeatureMappingIsMutable() {
+      if (!((bitField0_ & 0x00000001) != 0)) {
+        forwardFeatureMapping_ = mutableCopy(forwardFeatureMapping_);
+        bitField0_ |= 0x00000001;
+       }
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @return A list containing the forwardFeatureMapping.
+     */
+    public java.util.List<java.lang.Integer>
+        getForwardFeatureMappingList() {
+      return ((bitField0_ & 0x00000001) != 0) ?
+               java.util.Collections.unmodifiableList(forwardFeatureMapping_) : forwardFeatureMapping_;
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @return The count of forwardFeatureMapping.
+     */
+    public int getForwardFeatureMappingCount() {
+      return forwardFeatureMapping_.size();
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @param index The index of the element to return.
+     * @return The forwardFeatureMapping at the given index.
+     */
+    public int getForwardFeatureMapping(int index) {
+      return forwardFeatureMapping_.getInt(index);
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @param index The index to set the value at.
+     * @param value The forwardFeatureMapping to set.
+     * @return This builder for chaining.
+     */
+    public Builder setForwardFeatureMapping(
+        int index, int value) {
+      ensureForwardFeatureMappingIsMutable();
+      forwardFeatureMapping_.setInt(index, value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @param value The forwardFeatureMapping to add.
+     * @return This builder for chaining.
+     */
+    public Builder addForwardFeatureMapping(int value) {
+      ensureForwardFeatureMappingIsMutable();
+      forwardFeatureMapping_.addInt(value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @param values The forwardFeatureMapping to add.
+     * @return This builder for chaining.
+     */
+    public Builder addAllForwardFeatureMapping(
+        java.lang.Iterable<? extends java.lang.Integer> values) {
+      ensureForwardFeatureMappingIsMutable();
+      com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          values, forwardFeatureMapping_);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 forward_feature_mapping = 4;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearForwardFeatureMapping() {
+      forwardFeatureMapping_ = emptyIntList();
+      bitField0_ = (bitField0_ & ~0x00000001);
+      onChanged();
+      return this;
+    }
+
+    private com.google.protobuf.Internal.IntList backwardFeatureMapping_ = emptyIntList();
+    private void ensureBackwardFeatureMappingIsMutable() {
+      if (!((bitField0_ & 0x00000002) != 0)) {
+        backwardFeatureMapping_ = mutableCopy(backwardFeatureMapping_);
+        bitField0_ |= 0x00000002;
+       }
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @return A list containing the backwardFeatureMapping.
+     */
+    public java.util.List<java.lang.Integer>
+        getBackwardFeatureMappingList() {
+      return ((bitField0_ & 0x00000002) != 0) ?
+               java.util.Collections.unmodifiableList(backwardFeatureMapping_) : backwardFeatureMapping_;
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @return The count of backwardFeatureMapping.
+     */
+    public int getBackwardFeatureMappingCount() {
+      return backwardFeatureMapping_.size();
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @param index The index of the element to return.
+     * @return The backwardFeatureMapping at the given index.
+     */
+    public int getBackwardFeatureMapping(int index) {
+      return backwardFeatureMapping_.getInt(index);
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @param index The index to set the value at.
+     * @param value The backwardFeatureMapping to set.
+     * @return This builder for chaining.
+     */
+    public Builder setBackwardFeatureMapping(
+        int index, int value) {
+      ensureBackwardFeatureMappingIsMutable();
+      backwardFeatureMapping_.setInt(index, value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @param value The backwardFeatureMapping to add.
+     * @return This builder for chaining.
+     */
+    public Builder addBackwardFeatureMapping(int value) {
+      ensureBackwardFeatureMappingIsMutable();
+      backwardFeatureMapping_.addInt(value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @param values The backwardFeatureMapping to add.
+     * @return This builder for chaining.
+     */
+    public Builder addAllBackwardFeatureMapping(
+        java.lang.Iterable<? extends java.lang.Integer> values) {
+      ensureBackwardFeatureMappingIsMutable();
+      com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          values, backwardFeatureMapping_);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated int32 backward_feature_mapping = 5;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearBackwardFeatureMapping() {
+      backwardFeatureMapping_ = emptyIntList();
+      bitField0_ = (bitField0_ & ~0x00000002);
+      onChanged();
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.xgboost.XGBoostExternalModelProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.xgboost.XGBoostExternalModelProto)
+  private static final org.tribuo.common.xgboost.protos.XGBoostExternalModelProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.xgboost.protos.XGBoostExternalModelProto();
+  }
+
+  public static org.tribuo.common.xgboost.protos.XGBoostExternalModelProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<XGBoostExternalModelProto>
+      PARSER = new com.google.protobuf.AbstractParser<XGBoostExternalModelProto>() {
+    @java.lang.Override
+    public XGBoostExternalModelProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new XGBoostExternalModelProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<XGBoostExternalModelProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<XGBoostExternalModelProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostExternalModelProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProtoOrBuilder.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProtoOrBuilder.java
new file mode 100644
index 000000000..7e4ea8923
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostExternalModelProtoOrBuilder.java
@@ -0,0 +1,79 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+public interface XGBoostExternalModelProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.xgboost.XGBoostExternalModelProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  boolean hasMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  org.tribuo.protos.core.ModelDataProto getMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder();
+
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return Whether the converter field is set.
+   */
+  boolean hasConverter();
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return The converter.
+   */
+  org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter();
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   */
+  org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder();
+
+  /**
+   * <code>bytes model = 3;</code>
+   * @return The model.
+   */
+  com.google.protobuf.ByteString getModel();
+
+  /**
+   * <code>repeated int32 forward_feature_mapping = 4;</code>
+   * @return A list containing the forwardFeatureMapping.
+   */
+  java.util.List<java.lang.Integer> getForwardFeatureMappingList();
+  /**
+   * <code>repeated int32 forward_feature_mapping = 4;</code>
+   * @return The count of forwardFeatureMapping.
+   */
+  int getForwardFeatureMappingCount();
+  /**
+   * <code>repeated int32 forward_feature_mapping = 4;</code>
+   * @param index The index of the element to return.
+   * @return The forwardFeatureMapping at the given index.
+   */
+  int getForwardFeatureMapping(int index);
+
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @return A list containing the backwardFeatureMapping.
+   */
+  java.util.List<java.lang.Integer> getBackwardFeatureMappingList();
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @return The count of backwardFeatureMapping.
+   */
+  int getBackwardFeatureMappingCount();
+  /**
+   * <code>repeated int32 backward_feature_mapping = 5;</code>
+   * @param index The index of the element to return.
+   * @return The backwardFeatureMapping at the given index.
+   */
+  int getBackwardFeatureMapping(int index);
+}
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProto.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProto.java
new file mode 100644
index 000000000..2657de92e
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProto.java
@@ -0,0 +1,965 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+/**
+ * <pre>
+ *XGBoostModel proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.xgboost.XGBoostModelProto}
+ */
+public final class XGBoostModelProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.xgboost.XGBoostModelProto)
+    XGBoostModelProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use XGBoostModelProto.newBuilder() to construct.
+  private XGBoostModelProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private XGBoostModelProto() {
+    models_ = java.util.Collections.emptyList();
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new XGBoostModelProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private XGBoostModelProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 10: {
+            org.tribuo.protos.core.ModelDataProto.Builder subBuilder = null;
+            if (metadata_ != null) {
+              subBuilder = metadata_.toBuilder();
+            }
+            metadata_ = input.readMessage(org.tribuo.protos.core.ModelDataProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(metadata_);
+              metadata_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 18: {
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder subBuilder = null;
+            if (converter_ != null) {
+              subBuilder = converter_.toBuilder();
+            }
+            converter_ = input.readMessage(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(converter_);
+              converter_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 26: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              models_ = new java.util.ArrayList<com.google.protobuf.ByteString>();
+              mutable_bitField0_ |= 0x00000001;
+            }
+            models_.add(input.readBytes());
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      if (((mutable_bitField0_ & 0x00000001) != 0)) {
+        models_ = java.util.Collections.unmodifiableList(models_); // C
+      }
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostModelProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.xgboost.protos.XGBoostModelProto.class, org.tribuo.common.xgboost.protos.XGBoostModelProto.Builder.class);
+  }
+
+  public static final int METADATA_FIELD_NUMBER = 1;
+  private org.tribuo.protos.core.ModelDataProto metadata_;
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  @java.lang.Override
+  public boolean hasMetadata() {
+    return metadata_ != null;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProto getMetadata() {
+    return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+    return getMetadata();
+  }
+
+  public static final int CONVERTER_FIELD_NUMBER = 2;
+  private org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto converter_;
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return Whether the converter field is set.
+   */
+  @java.lang.Override
+  public boolean hasConverter() {
+    return converter_ != null;
+  }
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return The converter.
+   */
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter() {
+    return converter_ == null ? org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+  }
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder() {
+    return getConverter();
+  }
+
+  public static final int MODELS_FIELD_NUMBER = 3;
+  private java.util.List<com.google.protobuf.ByteString> models_;
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @return A list containing the models.
+   */
+  @java.lang.Override
+  public java.util.List<com.google.protobuf.ByteString>
+      getModelsList() {
+    return models_;
+  }
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @return The count of models.
+   */
+  public int getModelsCount() {
+    return models_.size();
+  }
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @param index The index of the element to return.
+   * @return The models at the given index.
+   */
+  public com.google.protobuf.ByteString getModels(int index) {
+    return models_.get(index);
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (metadata_ != null) {
+      output.writeMessage(1, getMetadata());
+    }
+    if (converter_ != null) {
+      output.writeMessage(2, getConverter());
+    }
+    for (int i = 0; i < models_.size(); i++) {
+      output.writeBytes(3, models_.get(i));
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (metadata_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(1, getMetadata());
+    }
+    if (converter_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(2, getConverter());
+    }
+    {
+      int dataSize = 0;
+      for (int i = 0; i < models_.size(); i++) {
+        dataSize += com.google.protobuf.CodedOutputStream
+          .computeBytesSizeNoTag(models_.get(i));
+      }
+      size += dataSize;
+      size += 1 * getModelsList().size();
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.xgboost.protos.XGBoostModelProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.xgboost.protos.XGBoostModelProto other = (org.tribuo.common.xgboost.protos.XGBoostModelProto) obj;
+
+    if (hasMetadata() != other.hasMetadata()) return false;
+    if (hasMetadata()) {
+      if (!getMetadata()
+          .equals(other.getMetadata())) return false;
+    }
+    if (hasConverter() != other.hasConverter()) return false;
+    if (hasConverter()) {
+      if (!getConverter()
+          .equals(other.getConverter())) return false;
+    }
+    if (!getModelsList()
+        .equals(other.getModelsList())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    if (hasMetadata()) {
+      hash = (37 * hash) + METADATA_FIELD_NUMBER;
+      hash = (53 * hash) + getMetadata().hashCode();
+    }
+    if (hasConverter()) {
+      hash = (37 * hash) + CONVERTER_FIELD_NUMBER;
+      hash = (53 * hash) + getConverter().hashCode();
+    }
+    if (getModelsCount() > 0) {
+      hash = (37 * hash) + MODELS_FIELD_NUMBER;
+      hash = (53 * hash) + getModelsList().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.xgboost.protos.XGBoostModelProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *XGBoostModel proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.xgboost.XGBoostModelProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.xgboost.XGBoostModelProto)
+      org.tribuo.common.xgboost.protos.XGBoostModelProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostModelProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.xgboost.protos.XGBoostModelProto.class, org.tribuo.common.xgboost.protos.XGBoostModelProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.xgboost.protos.XGBoostModelProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+      if (converterBuilder_ == null) {
+        converter_ = null;
+      } else {
+        converter_ = null;
+        converterBuilder_ = null;
+      }
+      models_ = java.util.Collections.emptyList();
+      bitField0_ = (bitField0_ & ~0x00000001);
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostModelProto getDefaultInstanceForType() {
+      return org.tribuo.common.xgboost.protos.XGBoostModelProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostModelProto build() {
+      org.tribuo.common.xgboost.protos.XGBoostModelProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostModelProto buildPartial() {
+      org.tribuo.common.xgboost.protos.XGBoostModelProto result = new org.tribuo.common.xgboost.protos.XGBoostModelProto(this);
+      int from_bitField0_ = bitField0_;
+      if (metadataBuilder_ == null) {
+        result.metadata_ = metadata_;
+      } else {
+        result.metadata_ = metadataBuilder_.build();
+      }
+      if (converterBuilder_ == null) {
+        result.converter_ = converter_;
+      } else {
+        result.converter_ = converterBuilder_.build();
+      }
+      if (((bitField0_ & 0x00000001) != 0)) {
+        models_ = java.util.Collections.unmodifiableList(models_);
+        bitField0_ = (bitField0_ & ~0x00000001);
+      }
+      result.models_ = models_;
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.xgboost.protos.XGBoostModelProto) {
+        return mergeFrom((org.tribuo.common.xgboost.protos.XGBoostModelProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.xgboost.protos.XGBoostModelProto other) {
+      if (other == org.tribuo.common.xgboost.protos.XGBoostModelProto.getDefaultInstance()) return this;
+      if (other.hasMetadata()) {
+        mergeMetadata(other.getMetadata());
+      }
+      if (other.hasConverter()) {
+        mergeConverter(other.getConverter());
+      }
+      if (!other.models_.isEmpty()) {
+        if (models_.isEmpty()) {
+          models_ = other.models_;
+          bitField0_ = (bitField0_ & ~0x00000001);
+        } else {
+          ensureModelsIsMutable();
+          models_.addAll(other.models_);
+        }
+        onChanged();
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.xgboost.protos.XGBoostModelProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.xgboost.protos.XGBoostModelProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private org.tribuo.protos.core.ModelDataProto metadata_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> metadataBuilder_;
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return Whether the metadata field is set.
+     */
+    public boolean hasMetadata() {
+      return metadataBuilder_ != null || metadata_ != null;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return The metadata.
+     */
+    public org.tribuo.protos.core.ModelDataProto getMetadata() {
+      if (metadataBuilder_ == null) {
+        return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      } else {
+        return metadataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        metadata_ = value;
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(
+        org.tribuo.protos.core.ModelDataProto.Builder builderForValue) {
+      if (metadataBuilder_ == null) {
+        metadata_ = builderForValue.build();
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder mergeMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (metadata_ != null) {
+          metadata_ =
+            org.tribuo.protos.core.ModelDataProto.newBuilder(metadata_).mergeFrom(value).buildPartial();
+        } else {
+          metadata_ = value;
+        }
+        onChanged();
+      } else {
+        metadataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder clearMetadata() {
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+        onChanged();
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProto.Builder getMetadataBuilder() {
+      
+      onChanged();
+      return getMetadataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+      if (metadataBuilder_ != null) {
+        return metadataBuilder_.getMessageOrBuilder();
+      } else {
+        return metadata_ == null ?
+            org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> 
+        getMetadataFieldBuilder() {
+      if (metadataBuilder_ == null) {
+        metadataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder>(
+                getMetadata(),
+                getParentForChildren(),
+                isClean());
+        metadata_ = null;
+      }
+      return metadataBuilder_;
+    }
+
+    private org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto converter_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder> converterBuilder_;
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     * @return Whether the converter field is set.
+     */
+    public boolean hasConverter() {
+      return converterBuilder_ != null || converter_ != null;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     * @return The converter.
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter() {
+      if (converterBuilder_ == null) {
+        return converter_ == null ? org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+      } else {
+        return converterBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder setConverter(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto value) {
+      if (converterBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        converter_ = value;
+        onChanged();
+      } else {
+        converterBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder setConverter(
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder builderForValue) {
+      if (converterBuilder_ == null) {
+        converter_ = builderForValue.build();
+        onChanged();
+      } else {
+        converterBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder mergeConverter(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto value) {
+      if (converterBuilder_ == null) {
+        if (converter_ != null) {
+          converter_ =
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.newBuilder(converter_).mergeFrom(value).buildPartial();
+        } else {
+          converter_ = value;
+        }
+        onChanged();
+      } else {
+        converterBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public Builder clearConverter() {
+      if (converterBuilder_ == null) {
+        converter_ = null;
+        onChanged();
+      } else {
+        converter_ = null;
+        converterBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder getConverterBuilder() {
+      
+      onChanged();
+      return getConverterFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder() {
+      if (converterBuilder_ != null) {
+        return converterBuilder_.getMessageOrBuilder();
+      } else {
+        return converter_ == null ?
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance() : converter_;
+      }
+    }
+    /**
+     * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder> 
+        getConverterFieldBuilder() {
+      if (converterBuilder_ == null) {
+        converterBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder>(
+                getConverter(),
+                getParentForChildren(),
+                isClean());
+        converter_ = null;
+      }
+      return converterBuilder_;
+    }
+
+    private java.util.List<com.google.protobuf.ByteString> models_ = java.util.Collections.emptyList();
+    private void ensureModelsIsMutable() {
+      if (!((bitField0_ & 0x00000001) != 0)) {
+        models_ = new java.util.ArrayList<com.google.protobuf.ByteString>(models_);
+        bitField0_ |= 0x00000001;
+       }
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @return A list containing the models.
+     */
+    public java.util.List<com.google.protobuf.ByteString>
+        getModelsList() {
+      return ((bitField0_ & 0x00000001) != 0) ?
+               java.util.Collections.unmodifiableList(models_) : models_;
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @return The count of models.
+     */
+    public int getModelsCount() {
+      return models_.size();
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @param index The index of the element to return.
+     * @return The models at the given index.
+     */
+    public com.google.protobuf.ByteString getModels(int index) {
+      return models_.get(index);
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @param index The index to set the value at.
+     * @param value The models to set.
+     * @return This builder for chaining.
+     */
+    public Builder setModels(
+        int index, com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  ensureModelsIsMutable();
+      models_.set(index, value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @param value The models to add.
+     * @return This builder for chaining.
+     */
+    public Builder addModels(com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  ensureModelsIsMutable();
+      models_.add(value);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @param values The models to add.
+     * @return This builder for chaining.
+     */
+    public Builder addAllModels(
+        java.lang.Iterable<? extends com.google.protobuf.ByteString> values) {
+      ensureModelsIsMutable();
+      com.google.protobuf.AbstractMessageLite.Builder.addAll(
+          values, models_);
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>repeated bytes models = 3;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearModels() {
+      models_ = java.util.Collections.emptyList();
+      bitField0_ = (bitField0_ & ~0x00000001);
+      onChanged();
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.xgboost.XGBoostModelProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.xgboost.XGBoostModelProto)
+  private static final org.tribuo.common.xgboost.protos.XGBoostModelProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.xgboost.protos.XGBoostModelProto();
+  }
+
+  public static org.tribuo.common.xgboost.protos.XGBoostModelProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<XGBoostModelProto>
+      PARSER = new com.google.protobuf.AbstractParser<XGBoostModelProto>() {
+    @java.lang.Override
+    public XGBoostModelProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new XGBoostModelProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<XGBoostModelProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<XGBoostModelProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostModelProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProtoOrBuilder.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProtoOrBuilder.java
new file mode 100644
index 000000000..7c4fda25e
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostModelProtoOrBuilder.java
@@ -0,0 +1,56 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+public interface XGBoostModelProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.xgboost.XGBoostModelProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  boolean hasMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  org.tribuo.protos.core.ModelDataProto getMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder();
+
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return Whether the converter field is set.
+   */
+  boolean hasConverter();
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   * @return The converter.
+   */
+  org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getConverter();
+  /**
+   * <code>.tribuo.common.xgboost.XGBoostOutputConverterProto converter = 2;</code>
+   */
+  org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder getConverterOrBuilder();
+
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @return A list containing the models.
+   */
+  java.util.List<com.google.protobuf.ByteString> getModelsList();
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @return The count of models.
+   */
+  int getModelsCount();
+  /**
+   * <code>repeated bytes models = 3;</code>
+   * @param index The index of the element to return.
+   * @return The models at the given index.
+   */
+  com.google.protobuf.ByteString getModels(int index);
+}
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProto.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProto.java
new file mode 100644
index 000000000..b67b32b83
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProto.java
@@ -0,0 +1,817 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+/**
+ * <pre>
+ *XGBoostOutputConverter redirect proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.xgboost.XGBoostOutputConverterProto}
+ */
+public final class XGBoostOutputConverterProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.xgboost.XGBoostOutputConverterProto)
+    XGBoostOutputConverterProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use XGBoostOutputConverterProto.newBuilder() to construct.
+  private XGBoostOutputConverterProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private XGBoostOutputConverterProto() {
+    className_ = "";
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new XGBoostOutputConverterProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private XGBoostOutputConverterProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 8: {
+
+            version_ = input.readInt32();
+            break;
+          }
+          case 18: {
+            java.lang.String s = input.readStringRequireUtf8();
+
+            className_ = s;
+            break;
+          }
+          case 26: {
+            com.google.protobuf.Any.Builder subBuilder = null;
+            if (serializedData_ != null) {
+              subBuilder = serializedData_.toBuilder();
+            }
+            serializedData_ = input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(serializedData_);
+              serializedData_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.class, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder.class);
+  }
+
+  public static final int VERSION_FIELD_NUMBER = 1;
+  private int version_;
+  /**
+   * <code>int32 version = 1;</code>
+   * @return The version.
+   */
+  @java.lang.Override
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+    return version_;
+  }
+
+  public static final int CLASS_NAME_FIELD_NUMBER = 2;
+  private volatile java.lang.Object className_;
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The className.
+   */
+  @java.lang.Override
+  public java.lang.String getClassName() {
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+    if (ref instanceof java.lang.String) {
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+      java.lang.String s = bs.toStringUtf8();
+      className_ = s;
+      return s;
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+  /**
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+   * @return The bytes for className.
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+  public com.google.protobuf.ByteString
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+    if (ref instanceof java.lang.String) {
+      com.google.protobuf.ByteString b = 
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+              (java.lang.String) ref);
+      className_ = b;
+      return b;
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+
+  public static final int SERIALIZED_DATA_FIELD_NUMBER = 3;
+  private com.google.protobuf.Any serializedData_;
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return Whether the serializedData field is set.
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+  @java.lang.Override
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+   * <code>.google.protobuf.Any serialized_data = 3;</code>
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+      output.writeMessage(3, getSerializedData());
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+  @java.lang.Override
+  public int getSerializedSize() {
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+    size = 0;
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+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto other = (org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto) obj;
+
+    if (getVersion()
+        != other.getVersion()) return false;
+    if (!getClassName()
+        .equals(other.getClassName())) return false;
+    if (hasSerializedData() != other.hasSerializedData()) return false;
+    if (hasSerializedData()) {
+      if (!getSerializedData()
+          .equals(other.getSerializedData())) return false;
+    }
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + VERSION_FIELD_NUMBER;
+    hash = (53 * hash) + getVersion();
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+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *XGBoostOutputConverter redirect proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.xgboost.XGBoostOutputConverterProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.xgboost.XGBoostOutputConverterProto)
+      org.tribuo.common.xgboost.protos.XGBoostOutputConverterProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.class, org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      version_ = 0;
+
+      className_ = "";
+
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = null;
+      } else {
+        serializedData_ = null;
+        serializedDataBuilder_ = null;
+      }
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.xgboost.protos.TribuoXgboost.internal_static_tribuo_common_xgboost_XGBoostOutputConverterProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getDefaultInstanceForType() {
+      return org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto build() {
+      org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto buildPartial() {
+      org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto result = new org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto(this);
+      result.version_ = version_;
+      result.className_ = className_;
+      if (serializedDataBuilder_ == null) {
+        result.serializedData_ = serializedData_;
+      } else {
+        result.serializedData_ = serializedDataBuilder_.build();
+      }
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto) {
+        return mergeFrom((org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto other) {
+      if (other == org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto.getDefaultInstance()) return this;
+      if (other.getVersion() != 0) {
+        setVersion(other.getVersion());
+      }
+      if (!other.getClassName().isEmpty()) {
+        className_ = other.className_;
+        onChanged();
+      }
+      if (other.hasSerializedData()) {
+        mergeSerializedData(other.getSerializedData());
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+
+    private int version_ ;
+    /**
+     * <code>int32 version = 1;</code>
+     * @return The version.
+     */
+    @java.lang.Override
+    public int getVersion() {
+      return version_;
+    }
+    /**
+     * <code>int32 version = 1;</code>
+     * @param value The version to set.
+     * @return This builder for chaining.
+     */
+    public Builder setVersion(int value) {
+      
+      version_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 version = 1;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearVersion() {
+      
+      version_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private java.lang.Object className_ = "";
+    /**
+     * <code>string class_name = 2;</code>
+     * @return The className.
+     */
+    public java.lang.String getClassName() {
+      java.lang.Object ref = className_;
+      if (!(ref instanceof java.lang.String)) {
+        com.google.protobuf.ByteString bs =
+            (com.google.protobuf.ByteString) ref;
+        java.lang.String s = bs.toStringUtf8();
+        className_ = s;
+        return s;
+      } else {
+        return (java.lang.String) ref;
+      }
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @return The bytes for className.
+     */
+    public com.google.protobuf.ByteString
+        getClassNameBytes() {
+      java.lang.Object ref = className_;
+      if (ref instanceof String) {
+        com.google.protobuf.ByteString b = 
+            com.google.protobuf.ByteString.copyFromUtf8(
+                (java.lang.String) ref);
+        className_ = b;
+        return b;
+      } else {
+        return (com.google.protobuf.ByteString) ref;
+      }
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @param value The className to set.
+     * @return This builder for chaining.
+     */
+    public Builder setClassName(
+        java.lang.String value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  
+      className_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearClassName() {
+      
+      className_ = getDefaultInstance().getClassName();
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @param value The bytes for className to set.
+     * @return This builder for chaining.
+     */
+    public Builder setClassNameBytes(
+        com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  checkByteStringIsUtf8(value);
+      
+      className_ = value;
+      onChanged();
+      return this;
+    }
+
+    private com.google.protobuf.Any serializedData_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> serializedDataBuilder_;
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     * @return Whether the serializedData field is set.
+     */
+    public boolean hasSerializedData() {
+      return serializedDataBuilder_ != null || serializedData_ != null;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     * @return The serializedData.
+     */
+    public com.google.protobuf.Any getSerializedData() {
+      if (serializedDataBuilder_ == null) {
+        return serializedData_ == null ? com.google.protobuf.Any.getDefaultInstance() : serializedData_;
+      } else {
+        return serializedDataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder setSerializedData(com.google.protobuf.Any value) {
+      if (serializedDataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        serializedData_ = value;
+        onChanged();
+      } else {
+        serializedDataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder setSerializedData(
+        com.google.protobuf.Any.Builder builderForValue) {
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = builderForValue.build();
+        onChanged();
+      } else {
+        serializedDataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder mergeSerializedData(com.google.protobuf.Any value) {
+      if (serializedDataBuilder_ == null) {
+        if (serializedData_ != null) {
+          serializedData_ =
+            com.google.protobuf.Any.newBuilder(serializedData_).mergeFrom(value).buildPartial();
+        } else {
+          serializedData_ = value;
+        }
+        onChanged();
+      } else {
+        serializedDataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder clearSerializedData() {
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = null;
+        onChanged();
+      } else {
+        serializedData_ = null;
+        serializedDataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public com.google.protobuf.Any.Builder getSerializedDataBuilder() {
+      
+      onChanged();
+      return getSerializedDataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public com.google.protobuf.AnyOrBuilder getSerializedDataOrBuilder() {
+      if (serializedDataBuilder_ != null) {
+        return serializedDataBuilder_.getMessageOrBuilder();
+      } else {
+        return serializedData_ == null ?
+            com.google.protobuf.Any.getDefaultInstance() : serializedData_;
+      }
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> 
+        getSerializedDataFieldBuilder() {
+      if (serializedDataBuilder_ == null) {
+        serializedDataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder>(
+                getSerializedData(),
+                getParentForChildren(),
+                isClean());
+        serializedData_ = null;
+      }
+      return serializedDataBuilder_;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.xgboost.XGBoostOutputConverterProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.xgboost.XGBoostOutputConverterProto)
+  private static final org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto();
+  }
+
+  public static org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<XGBoostOutputConverterProto>
+      PARSER = new com.google.protobuf.AbstractParser<XGBoostOutputConverterProto>() {
+    @java.lang.Override
+    public XGBoostOutputConverterProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new XGBoostOutputConverterProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<XGBoostOutputConverterProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<XGBoostOutputConverterProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProtoOrBuilder.java b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProtoOrBuilder.java
new file mode 100644
index 000000000..b8cfcd08b
--- /dev/null
+++ b/Common/XGBoost/src/main/java/org/tribuo/common/xgboost/protos/XGBoostOutputConverterProtoOrBuilder.java
@@ -0,0 +1,42 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-xgboost.proto
+
+package org.tribuo.common.xgboost.protos;
+
+public interface XGBoostOutputConverterProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.xgboost.XGBoostOutputConverterProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>int32 version = 1;</code>
+   * @return The version.
+   */
+  int getVersion();
+
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The className.
+   */
+  java.lang.String getClassName();
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The bytes for className.
+   */
+  com.google.protobuf.ByteString
+      getClassNameBytes();
+
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return Whether the serializedData field is set.
+   */
+  boolean hasSerializedData();
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return The serializedData.
+   */
+  com.google.protobuf.Any getSerializedData();
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   */
+  com.google.protobuf.AnyOrBuilder getSerializedDataOrBuilder();
+}
diff --git a/Common/XGBoost/src/main/resources/protos/tribuo-xgboost.proto b/Common/XGBoost/src/main/resources/protos/tribuo-xgboost.proto
new file mode 100644
index 000000000..7b33f59d6
--- /dev/null
+++ b/Common/XGBoost/src/main/resources/protos/tribuo-xgboost.proto
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = "proto3";
+
+/*
+ * Protos for serializing Tribuo's XGBoost models.
+ */
+package tribuo.common.xgboost;
+
+option java_multiple_files = true;
+option java_package = "org.tribuo.common.xgboost.protos";
+
+// We use Any to encode polymorphism
+import "google/protobuf/any.proto";
+
+// Import Tribuo's core protos
+import "tribuo-core.proto";
+
+/*
+XGBoostOutputConverter redirect proto
+ */
+message XGBoostOutputConverterProto {
+  int32 version = 1;
+  string class_name = 2;
+  google.protobuf.Any serialized_data = 3;
+}
+
+/*
+XGBoostModel proto
+ */
+message XGBoostModelProto {
+  tribuo.core.ModelDataProto metadata = 1;
+  XGBoostOutputConverterProto converter = 2;
+  repeated bytes models = 3;
+}
+
+/*
+XGBoostExternalModel proto
+ */
+message XGBoostExternalModelProto {
+  tribuo.core.ModelDataProto metadata = 1;
+  XGBoostOutputConverterProto converter = 2;
+  bytes model = 3;
+  repeated int32 forward_feature_mapping = 4;
+  repeated int32 backward_feature_mapping = 5;
+}
diff --git a/Core/src/test/java/org/tribuo/test/Helpers.java b/Core/src/test/java/org/tribuo/test/Helpers.java
index 4a3df7bd2..7173b3fec 100644
--- a/Core/src/test/java/org/tribuo/test/Helpers.java
+++ b/Core/src/test/java/org/tribuo/test/Helpers.java
@@ -204,7 +204,7 @@ public static <U extends Message, T extends ProtoSerializable<U>> T testProtoSer
         return deser;
     }
 
-    public static <T extends Output<T>> Model<T> testModelProtoSerialization(Model<T> model, Class<T> outputClazz, Dataset<T> data) {
+    public static <T extends Output<T>> Model<T> testModelProtoSerialization(Model<T> model, Class<T> outputClazz, Iterable<Example<T>> data) {
         // test provenance marshalling
         testProvenanceMarshalling(model.getProvenance());
 
diff --git a/Interop/Core/src/main/java/org/tribuo/interop/ExternalModel.java b/Interop/Core/src/main/java/org/tribuo/interop/ExternalModel.java
index 2e141d420..b6ea9ba22 100644
--- a/Interop/Core/src/main/java/org/tribuo/interop/ExternalModel.java
+++ b/Interop/Core/src/main/java/org/tribuo/interop/ExternalModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -284,4 +285,31 @@ protected static <T extends Output<T>> ImmutableOutputInfo<T> createOutputInfo(O
         return factory.constructInfoForExternalModel(outputs);
     }
 
+    /**
+     * Checks if the feature mappings are valid for the supplied feature map.
+     * @param featureForwardMapping The forward feature mapping.
+     * @param featureBackwardMapping The backward feature mapping.
+     * @param featureDomain The feature domain.
+     * @return True if the feature mapping is valid (the forward & backward mappings are a bijection and the same size as the feature domain).
+     */
+    protected static boolean validateFeatureMapping(int[] featureForwardMapping, int[] featureBackwardMapping, ImmutableFeatureMap featureDomain) {
+        if (featureBackwardMapping.length != featureForwardMapping.length) {
+            return false;
+        } else if (featureBackwardMapping.length != featureDomain.size()) {
+            return false;
+        } else {
+            // check bijection
+            Set<Integer> seenIndices = new HashSet<>();
+            for (int tribuoId = 0; tribuoId < featureForwardMapping.length; tribuoId++) {
+                int mappingId = featureForwardMapping[tribuoId];
+                if (featureBackwardMapping[mappingId] != tribuoId) {
+                    // not a bijection
+                    return false;
+                }
+                seenIndices.add(mappingId);
+            }
+            // check for duplicate mapping
+            return seenIndices.size() == featureDomain.size();
+        }
+    }
 }
diff --git a/Regression/XGBoost/src/main/java/org/tribuo/regression/xgboost/XGBoostRegressionConverter.java b/Regression/XGBoost/src/main/java/org/tribuo/regression/xgboost/XGBoostRegressionConverter.java
index 5f7aa2640..f01fbe635 100644
--- a/Regression/XGBoost/src/main/java/org/tribuo/regression/xgboost/XGBoostRegressionConverter.java
+++ b/Regression/XGBoost/src/main/java/org/tribuo/regression/xgboost/XGBoostRegressionConverter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,15 @@
 
 package org.tribuo.regression.xgboost;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
 import org.tribuo.Example;
 import org.tribuo.ImmutableOutputInfo;
 import org.tribuo.Prediction;
 import org.tribuo.common.xgboost.XGBoostOutputConverter;
+import org.tribuo.common.xgboost.protos.XGBoostOutputConverterProto;
+import org.tribuo.protos.ProtoSerializableClass;
+import org.tribuo.protos.ProtoUtil;
 import org.tribuo.regression.Regressor;
 
 import java.util.ArrayList;
@@ -30,14 +35,36 @@
  * <p>
  * Instances of this class are stateless and thread-safe.
  */
+@ProtoSerializableClass(version = XGBoostRegressionConverter.CURRENT_VERSION)
 public final class XGBoostRegressionConverter implements XGBoostOutputConverter<Regressor> {
     private static final long serialVersionUID = 1L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     /**
      * Construct an XGBoostRegressionConverter.
      */
     public XGBoostRegressionConverter() {}
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    public static XGBoostRegressionConverter deserializeFromProto(int version, String className, Any message) {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        if (message.getValue() != ByteString.EMPTY) {
+            throw new IllegalArgumentException("Invalid proto");
+        }
+        return new XGBoostRegressionConverter();
+    }
+
     @Override
     public boolean generatesProbabilities() {
         return false;
@@ -76,4 +103,13 @@ public List<Prediction<Regressor>> convertBatchOutput(ImmutableOutputInfo<Regres
         return predictions;
     }
 
+    @Override
+    public XGBoostOutputConverterProto serialize() {
+        return ProtoUtil.serialize(this);
+    }
+
+    @Override
+    public Class<Regressor> getTypeWitness() {
+        return Regressor.class;
+    }
 }
diff --git a/Regression/XGBoost/src/test/java/org/tribuo/regression/xgboost/TestXGBoost.java b/Regression/XGBoost/src/test/java/org/tribuo/regression/xgboost/TestXGBoost.java
index 040f14e73..79e7c74e4 100644
--- a/Regression/XGBoost/src/test/java/org/tribuo/regression/xgboost/TestXGBoost.java
+++ b/Regression/XGBoost/src/test/java/org/tribuo/regression/xgboost/TestXGBoost.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,7 @@ public void testMultiDenseData() {
         Pair<Dataset<Regressor>,Dataset<Regressor>> p = RegressionDataGenerator.multiDimDenseTrainTest();
         Model<Regressor> model = testXGBoost(p);
         Helpers.testModelSerialization(model,Regressor.class);
+        Helpers.testModelProtoSerialization(model, Regressor.class, p.getB());
     }
 
     @Test