diff --git a/karate-core2/src/main/java/com/intuit/karate/data/JsonUtils.java b/karate-core2/src/main/java/com/intuit/karate/data/JsonUtils.java
index 64f79975b..cb54e648b 100644
--- a/karate-core2/src/main/java/com/intuit/karate/data/JsonUtils.java
+++ b/karate-core2/src/main/java/com/intuit/karate/data/JsonUtils.java
@@ -25,6 +25,7 @@
 
 import com.intuit.karate.FileUtils;
 import com.intuit.karate.ScriptValue;
+import com.intuit.karate.graal.JsValue;
 import com.jayway.jsonpath.Configuration;
 import com.jayway.jsonpath.Option;
 import com.jayway.jsonpath.spi.json.JsonProvider;
@@ -35,6 +36,7 @@
 import de.siegmar.fastcsv.reader.CsvReader;
 import de.siegmar.fastcsv.reader.CsvRow;
 import de.siegmar.fastcsv.writer.CsvWriter;
+import java.io.IOException;
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.util.ArrayList;
@@ -42,8 +44,11 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import net.minidev.json.JSONStyle;
 import net.minidev.json.JSONValue;
 import net.minidev.json.parser.JSONParser;
+import net.minidev.json.reader.JsonWriter;
+import net.minidev.json.reader.JsonWriterI;
 import org.yaml.snakeyaml.Yaml;
 import org.yaml.snakeyaml.constructor.SafeConstructor;
 
@@ -57,10 +62,19 @@ private JsonUtils() {
         // only static methods
     }
 
+    private static class JsValueWriter implements JsonWriterI<JsValue> {
+
+        @Override
+        public <E extends JsValue> void writeJSONString(E value, Appendable out, JSONStyle compression) throws IOException {
+            JsonWriter.toStringWriter.writeJSONString("\"#" + value.type + "\"", out, compression);
+        }
+
+    }
+
     static {
+        JSONValue.registerWriter(JsValue.class, new JsValueWriter());
         // ensure that even if jackson (databind?) is on the classpath, don't switch provider
         Configuration.setDefaults(new Configuration.Defaults() {
-
             private final JsonProvider jsonProvider = new JsonSmartJsonProvider();
             private final MappingProvider mappingProvider = new JsonSmartMappingProvider();
 
diff --git a/karate-core2/src/main/java/com/intuit/karate/graal/JsEngine.java b/karate-core2/src/main/java/com/intuit/karate/graal/JsEngine.java
index 0acd2a270..bfa7534c0 100644
--- a/karate-core2/src/main/java/com/intuit/karate/graal/JsEngine.java
+++ b/karate-core2/src/main/java/com/intuit/karate/graal/JsEngine.java
@@ -63,12 +63,7 @@ private static class JsContext {
         }
 
         Value eval(String exp) {
-            try {
-                return context.eval(JS, exp);
-            } catch (Exception e) {
-                logger.error("js eval failed: {} - {}", e, exp);
-                throw new RuntimeException(e);
-            }
+            return context.eval(JS, exp);
         }
 
     }
@@ -91,11 +86,14 @@ public static void remove() {
 
     public static JsEngine local() {
         Engine engine = GLOBAL_JS_CONTEXT.get().context.getEngine();
-        JsEngine je = new JsEngine(new JsContext(engine));
-        Value bindings = global().bindings();
+        return new JsEngine(new JsContext(engine));
+    }
+
+    public static JsEngine localWithGlobalBindings() {
+        JsEngine je = local();
+        Value bindings = global().jc.bindings;
         for (String key : bindings.getMemberKeys()) {
-            Value v = bindings.getMember(key);
-            je.putValue(key, v);
+            je.putValue(key, bindings.getMember(key));
         }
         return je;
     }
@@ -114,6 +112,10 @@ private JsEngine(JsContext sc) {
         this.jc = sc;
     }
 
+    public Context getGraalContext() {
+        return jc.context;
+    }
+
     public Value bindings() {
         return jc.bindings;
     }
@@ -141,7 +143,7 @@ public void put(String key, Object value) {
     public void putAll(Map<String, Object> map) {
         map.forEach((k, v) -> put(k, v));
     }
-    
+
     public boolean hasMember(String key) {
         return jc.bindings.hasMember(key);
     }
@@ -165,10 +167,10 @@ public String toJson(JsValue jv) {
 
     public void putValue(String key, Value v) {
         if (v.isHostObject()) {
-            bindings().putMember(key, v.asHostObject());
+            jc.bindings.putMember(key, v.asHostObject());
         } else if (v.canExecute()) {
             Value fun = evalForValue("(" + v.toString() + ")");
-            bindings().putMember(key, fun);
+            jc.bindings.putMember(key, fun);
         } else {
             put(key, JsValue.toJava(v));
         }
diff --git a/karate-core2/src/main/java/com/intuit/karate/graal/JsValue.java b/karate-core2/src/main/java/com/intuit/karate/graal/JsValue.java
index 53b5f81e5..5f6bbf6eb 100644
--- a/karate-core2/src/main/java/com/intuit/karate/graal/JsValue.java
+++ b/karate-core2/src/main/java/com/intuit/karate/graal/JsValue.java
@@ -30,6 +30,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import org.graalvm.polyglot.Context;
 import org.graalvm.polyglot.Value;
 
 /**
@@ -45,7 +46,7 @@ public static enum Type {
         OTHER
     }
 
-    private final Value original;
+    private Value original;
     private final Object value;
     public final Type type;
 
@@ -109,10 +110,22 @@ public List getAsList() {
         return (List) value;
     }
 
+    public void switchContext(JsEngine js) {
+        Context context = original.getContext();
+        if (context != null && !context.equals(js.getGraalContext())) {
+            String temp = "(" + original.toString() + ")";
+            original = js.evalForValue(temp);
+        }
+    }
+
     public Value getOriginal() {
         return original;
     }
 
+    public void setOriginal(Value original) {
+        this.original = original;
+    }
+
     public JsValue execute(Object... args) {
         return new JsValue(original.execute(args));
     }
@@ -140,10 +153,6 @@ public boolean isOther() {
         return type == Type.OTHER;
     }
 
-    public String asString() {
-        return original.asString();
-    }
-
     @Override
     public String toString() {
         return original.toString();
diff --git a/karate-core2/src/main/java/com/intuit/karate/match/Match.java b/karate-core2/src/main/java/com/intuit/karate/match/Match.java
index 71e5d5347..5dc53972d 100644
--- a/karate-core2/src/main/java/com/intuit/karate/match/Match.java
+++ b/karate-core2/src/main/java/com/intuit/karate/match/Match.java
@@ -23,6 +23,7 @@
  */
 package com.intuit.karate.match;
 
+import com.intuit.karate.graal.JsEngine;
 import static com.intuit.karate.match.MatchResult.*;
 import java.util.HashMap;
 import java.util.Map;
@@ -69,8 +70,8 @@ public static MatchValue that(Object o) {
         return new MatchValue(MatchValue.parseIfJsonOrXml(o));
     }
 
-    public static MatchResult execute(MatchType matchType, MatchValue actual, MatchValue expected) {
-        MatchOperation mo = new MatchOperation(matchType, actual, expected);
+    public static MatchResult execute(JsEngine js, MatchType matchType, MatchValue actual, MatchValue expected) {
+        MatchOperation mo = new MatchOperation(js, matchType, actual, expected);
         mo.execute();
         if (mo.pass) {
             return PASS;
diff --git a/karate-core2/src/main/java/com/intuit/karate/match/MatchContext.java b/karate-core2/src/main/java/com/intuit/karate/match/MatchContext.java
index abac2c790..f2577443f 100644
--- a/karate-core2/src/main/java/com/intuit/karate/match/MatchContext.java
+++ b/karate-core2/src/main/java/com/intuit/karate/match/MatchContext.java
@@ -23,12 +23,15 @@
  */
 package com.intuit.karate.match;
 
+import com.intuit.karate.graal.JsEngine;
+
 /**
  *
  * @author pthomas3
  */
 public class MatchContext {
 
+    public final JsEngine JS;
     public final MatchOperation root;
     public final int depth;
     public final boolean xml;
@@ -36,7 +39,8 @@ public class MatchContext {
     public final String name;
     public final int index;
 
-    protected MatchContext(MatchOperation root, boolean xml, int depth, String path, String name, int index) {
+    protected MatchContext(JsEngine js, MatchOperation root, boolean xml, int depth, String path, String name, int index) {
+        this.JS = js;
         this.root = root;
         this.xml = xml;
         this.depth = depth;
@@ -48,19 +52,19 @@ protected MatchContext(MatchOperation root, boolean xml, int depth, String path,
     public MatchContext descend(String name) {
         if (xml) {
             String childPath = path.endsWith("/@") ? path + name : (depth == 0 ? "" : path) + "/" + name;
-            return new MatchContext(root, xml, depth + 1, childPath, name, -1);
+            return new MatchContext(JS, root, xml, depth + 1, childPath, name, -1);
         } else {
             boolean needsQuotes = name.indexOf('-') != -1 || name.indexOf(' ') != -1 || name.indexOf('.') != -1;
             String childPath = needsQuotes ? path + "['" + name + "']" : path + '.' + name;
-            return new MatchContext(root, xml, depth + 1, childPath, name, -1);
+            return new MatchContext(JS, root, xml, depth + 1, childPath, name, -1);
         }
     }
 
     public MatchContext descend(int index) {
         if (xml) {
-            return new MatchContext(root, xml, depth + 1, path + "[" + (index + 1) + "]", name, index);
+            return new MatchContext(JS, root, xml, depth + 1, path + "[" + (index + 1) + "]", name, index);
         } else {
-            return new MatchContext(root, xml, depth + 1, path + "[" + index + "]", name, index);
+            return new MatchContext(JS, root, xml, depth + 1, path + "[" + index + "]", name, index);
         }
     }
 
diff --git a/karate-core2/src/main/java/com/intuit/karate/match/MatchOperation.java b/karate-core2/src/main/java/com/intuit/karate/match/MatchOperation.java
index f4bc35bdc..8928db135 100644
--- a/karate-core2/src/main/java/com/intuit/karate/match/MatchOperation.java
+++ b/karate-core2/src/main/java/com/intuit/karate/match/MatchOperation.java
@@ -53,23 +53,33 @@ public class MatchOperation {
 
     boolean pass = true;
     String failReason;
-
+    
     public MatchOperation(MatchType type, MatchValue actual, MatchValue expected) {
-        this(null, type, actual, expected);
+        this(JsEngine.global(), null, type, actual, expected);
+    }    
+
+    public MatchOperation(JsEngine js, MatchType type, MatchValue actual, MatchValue expected) {
+        this(js, null, type, actual, expected);
+    }
+    
+    private MatchOperation(MatchContext context, MatchType type, MatchValue actual, MatchValue expected) {
+        this(null, context, type, actual, expected);
     }
 
-    public MatchOperation(MatchContext context, MatchType type, MatchValue actual, MatchValue expected) {
+    private MatchOperation(JsEngine js, MatchContext context, MatchType type, MatchValue actual, MatchValue expected) {
         this.type = type;
         this.actual = actual;
         this.expected = expected;
         if (context == null) {
+            if (js == null) {
+                js = JsEngine.global();
+            }
             this.failures = new ArrayList();
             if (actual.isXml()) {
-                this.context = new MatchContext(this, true, 0, "/", "", -1);
+                this.context = new MatchContext(js, this, true, 0, "/", "", -1);
             } else {
-                this.context = new MatchContext(this, false, 0, "$", "", -1);
+                this.context = new MatchContext(js, this, false, 0, "$", "", -1);
             }
-
         } else {
             this.context = context;
             this.failures = context.root.failures;
@@ -149,10 +159,9 @@ public boolean execute() {
                     List list = actual.getValue();
                     MatchType nestedMatchType = fromMatchEach();
                     int count = list.size();
-                    JsEngine jsEngine = JsEngine.global();
                     for (int i = 0; i < count; i++) {
                         Object o = list.get(i);
-                        jsEngine.put("_$", o);
+                        context.JS.put("_$", o);
                         MatchOperation mo = new MatchOperation(context.descend(i), nestedMatchType, new MatchValue(o), expected);
                         mo.execute();
                         if (!mo.pass) {
@@ -220,7 +229,7 @@ private boolean macroEqualsExpected(String expStr) {
                 MatchType nestedType = macroToMatchType(false, macro);
                 int startPos = matchTypeToStartPos(nestedType);
                 macro = macro.substring(startPos);
-                JsValue jv = JsEngine.evalGlobal(macro);
+                JsValue jv = context.JS.eval(macro);
                 MatchOperation mo = new MatchOperation(context, nestedType, actual, new MatchValue(jv.getValue()));
                 return mo.execute();
             } else if (macro.startsWith("[")) {
@@ -233,16 +242,15 @@ private boolean macroEqualsExpected(String expStr) {
                         String bracketContents = macro.substring(1, closeBracketPos);
                         List listAct = actual.getValue();
                         int listSize = listAct.size();
-                        JsEngine jsEngine = JsEngine.global();
-                        jsEngine.put("$", context.root.actual.getValue());
-                        jsEngine.put("_", listSize);
+                        context.JS.put("$", context.root.actual.getValue());
+                        context.JS.put("_", listSize);
                         String sizeExpr;
                         if (bracketContents.indexOf('_') != -1) { // #[_ < 5] 
                             sizeExpr = bracketContents;
                         } else { // #[5] | #[$.foo] 
                             sizeExpr = bracketContents + " == _";
                         }
-                        JsValue jv = jsEngine.eval(sizeExpr);
+                        JsValue jv = context.JS.eval(sizeExpr);
                         if (!jv.isTrue()) {
                             return fail("actual array length is " + listSize);
                         }
@@ -264,7 +272,7 @@ private boolean macroEqualsExpected(String expStr) {
                                 MatchType nestedType = macroToMatchType(true, macro); // match each
                                 int startPos = matchTypeToStartPos(nestedType);
                                 macro = macro.substring(startPos);
-                                JsValue jv = JsEngine.evalGlobal(macro);
+                                JsValue jv = context.JS.eval(macro);
                                 MatchOperation mo = new MatchOperation(context, nestedType, actual, new MatchValue(jv.getValue()));
                                 return mo.execute();
                             }
@@ -313,10 +321,9 @@ private boolean macroEqualsExpected(String expStr) {
                 }
                 macro = StringUtils.trimToNull(macro);
                 if (macro != null && questionPos != -1) {
-                    JsEngine jsEngine = JsEngine.global();
-                    jsEngine.put("$", context.root.actual.getValue());
-                    jsEngine.put("_", actual.getValue());
-                    JsValue jv = jsEngine.eval(macro);
+                    context.JS.put("$", context.root.actual.getValue());
+                    context.JS.put("_", actual.getValue());
+                    JsValue jv = context.JS.eval(macro);
                     if (!jv.isTrue()) {
                         return fail("evaluated to 'false'");
                     }
@@ -570,8 +577,9 @@ private static String collectFailureReasons(MatchOperation root) {
                 sb.append(prefix).append(mo.actual.getAsXmlString()).append('\n');
                 sb.append(prefix).append(mo.expected.getAsXmlString()).append('\n');
             } else {
+                MatchValue expected = mo.expected.getSortedLike(mo.actual);
                 sb.append(prefix).append(mo.actual.getWithinSingleQuotesIfString()).append('\n');
-                sb.append(prefix).append(mo.expected.getWithinSingleQuotesIfString()).append('\n');
+                sb.append(prefix).append(expected.getWithinSingleQuotesIfString()).append('\n');
             }
         }
         return sb.toString();
diff --git a/karate-core2/src/main/java/com/intuit/karate/match/MatchValue.java b/karate-core2/src/main/java/com/intuit/karate/match/MatchValue.java
index 6fbe688a6..24d5869f7 100644
--- a/karate-core2/src/main/java/com/intuit/karate/match/MatchValue.java
+++ b/karate-core2/src/main/java/com/intuit/karate/match/MatchValue.java
@@ -26,8 +26,11 @@
 import com.intuit.karate.XmlUtils;
 import com.intuit.karate.data.Json;
 import com.intuit.karate.data.JsonUtils;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import org.w3c.dom.Node;
 
 /**
@@ -177,6 +180,27 @@ public String getAsXmlString() {
             return getAsString();
         }
     }
+    
+    public MatchValue getSortedLike(MatchValue other) {
+        if (isMap() && other.isMap()) {
+            Map<String, Object> reference = other.getValue();
+            Map<String, Object> source = getValue();
+            Set<String> remainder = new LinkedHashSet(source.keySet());
+            Map<String, Object> result = new LinkedHashMap(source.size());
+            reference.keySet().forEach(key -> {
+                if (source.containsKey(key)) {
+                    result.put(key, source.get(key));
+                    remainder.remove(key);
+                }
+            });
+            for (String key : remainder) {
+                result.put(key, source.get(key));
+            }
+            return new MatchValue(result);
+        } else {
+            return this;
+        }
+    } 
 
     @Override
     public String toString() {
diff --git a/karate-core2/src/main/java/com/intuit/karate/runtime/FeatureRuntime.java b/karate-core2/src/main/java/com/intuit/karate/runtime/FeatureRuntime.java
index e52024b0a..64d64ea1c 100644
--- a/karate-core2/src/main/java/com/intuit/karate/runtime/FeatureRuntime.java
+++ b/karate-core2/src/main/java/com/intuit/karate/runtime/FeatureRuntime.java
@@ -26,30 +26,34 @@
 import com.intuit.karate.core.Feature;
 import com.intuit.karate.core.FeatureResult;
 import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  *
  * @author pthomas3
  */
 public class FeatureRuntime implements Runnable {
-    
+
     public final SuiteRuntime suite;
     public final FeatureRuntime rootFeature;
     public final ScenarioCall parentCall;
     public final Feature feature;
     public final FeatureResult result;
     private final ScenarioGenerator scenarios;
-    
+
+    public final Map<String, ScenarioCall.Result> FEATURE_CACHE = new HashMap();
+
     private PerfRuntime perfRuntime;
-    
+
     public Path getParentPath() {
         return feature.getPath().getParent();
     }
-    
+
     public Path getRootParentPath() {
         return rootFeature.getParentPath();
     }
-    
+
     public Path getPath() {
         return feature.getPath();
     }
@@ -57,20 +61,20 @@ public Path getPath() {
     public void setPerfRuntime(PerfRuntime perfRuntime) {
         this.perfRuntime = perfRuntime;
     }
-    
+
     public boolean isPerfMode() {
         return perfRuntime != null;
     }
 
     public PerfRuntime getPerfRuntime() {
         return perfRuntime;
-    }        
-    
+    }
+
     public FeatureRuntime(SuiteRuntime suite, Feature feature, boolean karateConfigDisabled) {
         this(suite, feature, ScenarioCall.NONE);
         parentCall.setKarateConfigDisabled(karateConfigDisabled);
     }
-    
+
     public FeatureRuntime(ScenarioCall call) {
         this(call.parentRuntime.featureRuntime.suite, call.feature, call);
     }
@@ -83,9 +87,9 @@ private FeatureRuntime(SuiteRuntime suite, Feature feature, ScenarioCall parentC
         result = new FeatureResult(suite.results, feature);
         scenarios = new ScenarioGenerator(this, feature.getSections().iterator());
     }
-    
+
     private ScenarioRuntime currentScenario;
-    
+
     public Variable getResultVariable() {
         if (currentScenario == null) {
             return Variable.NULL;
diff --git a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioCall.java b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioCall.java
index 444801a60..28e9f4135 100644
--- a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioCall.java
+++ b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioCall.java
@@ -100,12 +100,12 @@ public ScenarioCall(ScenarioRuntime parentRuntime, Feature feature) {
 
     public static class Result {
 
-        public final Variable result;
+        public final Variable value;
         public final Config config;
         public final Map<String, Variable> vars;
 
-        public Result(Variable result, Config config, Map<String, Variable> vars) {
-            this.result = result;
+        public Result(Variable value, Config config, Map<String, Variable> vars) {
+            this.value = value;
             this.config = config;
             this.vars = vars;
         }
diff --git a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioEngine.java b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioEngine.java
index 002eed9de..0d97758c3 100644
--- a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioEngine.java
+++ b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioEngine.java
@@ -32,6 +32,7 @@
 import com.intuit.karate.data.JsonUtils;
 import com.intuit.karate.exception.KarateException;
 import com.intuit.karate.graal.JsEngine;
+import com.intuit.karate.graal.JsValue;
 import com.intuit.karate.match.Match;
 import com.intuit.karate.match.MatchResult;
 import com.intuit.karate.match.MatchType;
@@ -68,19 +69,37 @@ public ScenarioEngine(Map<String, Variable> vars, Logger logger) {
         this.logger = logger;
     }
 
+    // not in constructor because it has to be on Runable.run() thread
     public void init() {
-        JsEngine.remove(); // reset JS engine for this thread
-        JS = JsEngine.global();
+        JS = JsEngine.local();
+    }
+
+    private void putJsBinding(String name, Variable v) {
+        switch (v.type) {
+            case JS_FUNCTION:
+                JsValue jv = v.getValue();
+                // important to ensure that the function is attached to the current context
+                // since it may have come from e.g. karate-config.js or a calling / parent feature
+                // this will update the wrapper variable if needed as a performance optimization
+                jv.switchContext(JS);
+                JS.put(name, jv);
+                break;
+            case XML:
+                JS.put(name, XmlUtils.toObject(v.getValue()));
+                break;
+            default:
+                JS.put(name, v.getValue());
+        }
     }
 
     public Variable eval(String exp) {
-        vars.forEach((k, v) -> JS.put(k, v.getValueForJsEngine()));
+        vars.forEach((k, v) -> putJsBinding(k, v));
         return new Variable(JS.eval(exp));
     }
 
     public void setHiddenVariable(String key, Object value) {
         if (value instanceof Variable) {
-            JS.put(key, ((Variable) value).getValue());
+            putJsBinding(key, (Variable) value);
         } else {
             JS.put(key, value);
         }
@@ -681,7 +700,7 @@ public MatchResult match(MatchType matchType, String expression, String path, St
             }
         }
         MatchValue actualValue = new MatchValue(actual.getValue());
-        return Match.execute(matchType, actualValue, expectedValue);
+        return Match.execute(JS, matchType, actualValue, expectedValue);
     }
 
     private static final Pattern VAR_AND_PATH_PATTERN = Pattern.compile("\\w+");
@@ -774,22 +793,73 @@ public static StringUtils.Pair parseCallArgs(String line) {
         return new StringUtils.Pair(line.substring(0, pos), StringUtils.trimToNull(line.substring(pos)));
     }
 
-    public Variable call(boolean callOnce, String exp, boolean reuseParentConfig) {
-        StringUtils.Pair pair = parseCallArgs(exp);
-        Variable called = evalKarateExpression(pair.left);
-        Variable arg = pair.right == null ? null : evalKarateExpression(pair.right);
+    private Variable call(ScenarioRuntime runtime, Variable called, Variable arg, boolean reuseParentConfig) {
         switch (called.type) {
             case JAVA_FUNCTION:
             case JS_FUNCTION:
                 return arg == null ? called.invokeFunction() : called.invokeFunction(new Object[]{arg.getValue()});
             case KARATE_FEATURE:
-                ScenarioRuntime runtime = ScenarioRuntime.LOCAL.get();
                 return callFeature(runtime, called.getValue(), arg, -1, reuseParentConfig);
             default:
                 throw new RuntimeException("not a callable feature or js function: " + called);
         }
     }
 
+    public Variable call(boolean callOnce, String exp, boolean reuseParentConfig) {
+        StringUtils.Pair pair = parseCallArgs(exp);
+        Variable called = evalKarateExpression(pair.left);
+        Variable arg = pair.right == null ? null : evalKarateExpression(pair.right);
+        ScenarioRuntime runtime = ScenarioRuntime.LOCAL.get();
+        if (callOnce) {
+            return callOnce(runtime, exp, called, arg, reuseParentConfig);
+        } else {
+            return call(runtime, called, arg, reuseParentConfig);
+        }
+    }
+
+    private Variable result(ScenarioRuntime runtime, ScenarioCall.Result result, boolean reuseParentConfig) {
+        if (reuseParentConfig) { // if shared scope
+            runtime.configure(new Config(result.config)); // re-apply config from time of snapshot
+            if (result.vars != null) {
+                vars.clear();
+                vars.putAll(copyVariables(false)); // clone for safety 
+            }
+        }
+        return result.value.copy(false); // clone result for safety       
+    }
+
+    private Variable callOnce(ScenarioRuntime runtime, String cacheKey, Variable called, Variable arg, boolean reuseParentConfig) {
+        // IMPORTANT: the call result is always shallow-cloned before returning
+        // so that call result (especially if a java Map) is not mutated by other scenarios
+        final Map<String, ScenarioCall.Result> CACHE = runtime.featureRuntime.FEATURE_CACHE;
+        ScenarioCall.Result result = CACHE.get(cacheKey);
+        if (result != null) {
+            runtime.logger.trace("callonce cache hit for: {}", cacheKey);
+            return result(runtime, result, reuseParentConfig);
+        }
+        long startTime = System.currentTimeMillis();
+        runtime.logger.trace("callonce waiting for lock: {}", cacheKey);
+        synchronized (CACHE) {
+            result = CACHE.get(cacheKey); // retry
+            if (result != null) {
+                long endTime = System.currentTimeMillis() - startTime;
+                runtime.logger.warn("this thread waited {} milliseconds for callonce lock: {}", endTime, cacheKey);
+                return result(runtime, result, reuseParentConfig);
+            }
+            // this thread is the 'winner'
+            runtime.logger.info(">> lock acquired, begin callonce: {}", cacheKey);
+            Variable resultValue = call(runtime, called, arg, reuseParentConfig);
+            // we clone result (and config) here, to snapshot state at the point the callonce was invoked
+            // this prevents the state from being clobbered by the subsequent steps of this
+            // first scenario that is about to use the result
+            Map<String, Variable> clonedVars = called.isKarateFeature() && reuseParentConfig ? copyVariables(false) : null;
+            result = new ScenarioCall.Result(resultValue.copy(false), new Config(runtime.getConfig()), clonedVars);
+            CACHE.put(cacheKey, result);
+            runtime.logger.info("<< lock released, cached callonce: {}", cacheKey);
+            return resultValue; // another routine will apply globally if needed
+        }
+    }
+
     public Variable callFeature(ScenarioRuntime runtime, Feature feature, Variable arg, int index, boolean reuseParentConfig) {
         if (arg == null || arg.isMap()) {
             ScenarioCall call = new ScenarioCall(runtime, feature);
diff --git a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioRuntime.java b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioRuntime.java
index 475968510..967858a95 100644
--- a/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioRuntime.java
+++ b/karate-core2/src/main/java/com/intuit/karate/runtime/ScenarioRuntime.java
@@ -391,6 +391,11 @@ public HttpRequest getPrevRequest() {
     public Config getConfig() {
         return config;
     }
+    
+    public void configure(Config config) {
+        this.config = config;
+        http = ScenarioHttpClient.construct(config);
+    }    
 
     public void updateConfigCookies(Map<String, Cookie> cookies) {
         if (cookies == null) {
diff --git a/karate-core2/src/main/java/com/intuit/karate/runtime/Variable.java b/karate-core2/src/main/java/com/intuit/karate/runtime/Variable.java
index ca5d1063a..7b0cd5271 100644
--- a/karate-core2/src/main/java/com/intuit/karate/runtime/Variable.java
+++ b/karate-core2/src/main/java/com/intuit/karate/runtime/Variable.java
@@ -34,6 +34,8 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.w3c.dom.Node;
 
 /**
@@ -42,6 +44,8 @@
  */
 public class Variable {
 
+    private static final Logger logger = LoggerFactory.getLogger(Variable.class);
+
     public static enum Type {
         NULL,
         BOOLEAN,
@@ -141,6 +145,10 @@ public boolean isOther() {
     public boolean isFunction() {
         return type == Type.JS_FUNCTION || type == Type.JAVA_FUNCTION;
     }
+    
+    public boolean isKarateFeature() {
+        return type == Type.KARATE_FEATURE;
+    }
 
     public boolean isTrue() {
         return type == Type.BOOLEAN && ((Boolean) value);
@@ -234,15 +242,6 @@ public String getAsPrettyString() {
         }
     }
 
-    public Object getValueForJsEngine() {
-        switch (type) {
-            case XML:
-                return XmlUtils.toObject(getValue());
-            default:
-                return value;
-        }
-    }
-
     public int getAsInt() {
         if (isNumber()) {
             return ((Number) value).intValue();
@@ -254,17 +253,15 @@ public int getAsInt() {
     public Variable copy(boolean deep) {
         switch (type) {
             case LIST:
-                if (deep) {
-                    return new Variable(JsonUtils.fromJsonString(getAsString()));
-                } else {
-                    return new Variable(new ArrayList((List) value));
-                }
             case MAP:
                 if (deep) {
-                    return new Variable(JsonUtils.fromJsonString(getAsString()));
-                } else {
-                    return new Variable(new LinkedHashMap((Map) value));
+                    try {
+                        return new Variable(JsonUtils.fromJsonString(getAsString()));
+                    } catch (Throwable t) {
+                        logger.warn("json deep clone failed, will fall-back to shallow: {}", t.getMessage());
+                    }
                 }
+                return isMap() ? new Variable(new LinkedHashMap((Map) value)) : new Variable(new ArrayList((List) value));
             case XML:
                 return new Variable(XmlUtils.toXmlDoc(getAsString()));
             default:
diff --git a/karate-core2/src/main/java/com/intuit/karate/template/TemplateEngineContext.java b/karate-core2/src/main/java/com/intuit/karate/template/TemplateEngineContext.java
index 71e3b19a6..37dea9abd 100644
--- a/karate-core2/src/main/java/com/intuit/karate/template/TemplateEngineContext.java
+++ b/karate-core2/src/main/java/com/intuit/karate/template/TemplateEngineContext.java
@@ -65,7 +65,7 @@ public TemplateEngineContext(IEngineContext wrapped, RequestCycle requestCycle)
     private JsEngine LOCAL_ENGINE;
 
     public JsValue eval(boolean queue, String exp) {
-        JsEngine je = JsEngine.local();
+        JsEngine je = JsEngine.localWithGlobalBindings();
         requestCycle.setLocalEngine(je);
         Set<String> variableNames = getVariableNames();
         if (variableNames.contains(ENGINE)) {
diff --git a/karate-core2/src/test/java/com/intuit/karate/runtime/ScenarioRuntimeTest.java b/karate-core2/src/test/java/com/intuit/karate/runtime/ScenarioRuntimeTest.java
index e0023ff64..628122d0c 100644
--- a/karate-core2/src/test/java/com/intuit/karate/runtime/ScenarioRuntimeTest.java
+++ b/karate-core2/src/test/java/com/intuit/karate/runtime/ScenarioRuntimeTest.java
@@ -98,12 +98,22 @@ void testCallKarateFeature() {
                 "def res = call read('called1.feature') [{ foo: 'bar' }]"
         );  
         matchVarEquals("res", "[{ a: 1, b: 'bar', foo: { hello: 'world' }, configSource: 'normal', __arg: { foo: 'bar' }, __loop: 0 }]"); 
-//        run(
-//                "def b = 'bar'",
-//                "def fun = function(i){ return { index: i } }",
-//                "def res = call read('called1.feature') fun"
-//        );  
-//        matchVarEquals("res", "[{ a: 1, b: 'bar', foo: { hello: 'world' }, configSource: 'normal', __arg: { index: 0 }, __loop: 0 }]");         
+        run(
+                "def b = 'bar'",
+                "def fun = function(i){ if (i == 1) return null; return { index: i } }",
+                "def res = call read('called1.feature') fun"
+        );  
+        matchVarEquals("res", "[{ a: 1, b: 'bar', foo: { hello: 'world' }, configSource: 'normal', __arg: { index: 0 }, __loop: 0, index: 0, fun: '#ignore' }]");         
+    }
+    
+    @Test
+    void testCallOnce() {
+        run(
+                "def uuid = function(){ return java.util.UUID.randomUUID() + '' }",
+                "def first = callonce uuid",
+                "def second = callonce uuid"                
+        );
+        matchVarEquals("first", get("second"));
     }
 
 }