diff --git a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/CosmosDbIO.scala b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/CosmosDbIO.scala
index 83b5121bde..288477a4b8 100644
--- a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/CosmosDbIO.scala
+++ b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/CosmosDbIO.scala
@@ -25,11 +25,11 @@ import org.bson.Document
 trait CosmosDbIO[T] extends ScioIO[T] {}
 
 case class ReadCosmosDdIO(
-  endpoint: String = null,
-  key: String = null,
-  database: String = null,
-  container: String = null,
-  query: String = null
+  endpoint: String,
+  key: String,
+  database: String,
+  container: String,
+  query: String
 ) extends CosmosDbIO[Document] {
   override type ReadP = Unit
   override type WriteP = Nothing
diff --git a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedReader.scala b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedReader.scala
index b1e2031a60..9369f1f088 100644
--- a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedReader.scala
+++ b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedReader.scala
@@ -17,19 +17,20 @@
 package com.spotify.scio.cosmosdb.read
 
 import com.azure.cosmos.models.CosmosQueryRequestOptions
-import com.azure.cosmos.{CosmosClient, CosmosClientBuilder}
-import org.apache.beam.sdk.annotations.Experimental
-import org.apache.beam.sdk.annotations.Experimental.Kind
+import com.azure.cosmos.{ CosmosClient, CosmosClientBuilder }
+import com.spotify.scio.annotations.experimental
 import org.apache.beam.sdk.io.BoundedSource
 import org.bson.Document
 import org.slf4j.LoggerFactory
 
-@Experimental(Kind.SOURCE_SINK)
+@experimental
 private[read] class CosmosDbBoundedReader(cosmosSource: CosmosDbBoundedSource)
     extends BoundedSource.BoundedReader[Document] {
   private val log = LoggerFactory.getLogger(getClass)
   private var maybeClient: Option[CosmosClient] = None
   private var maybeIterator: Option[java.util.Iterator[Document]] = None
+  @volatile private var current: Option[Document] = None
+  @volatile private var recordsReturned = 0L
 
   override def start(): Boolean = {
     maybeClient = Some(
@@ -55,19 +56,26 @@ private[read] class CosmosDbBoundedReader(cosmosSource: CosmosDbBoundedSource)
         .iterator()
     }
 
-    true
+    advance()
   }
 
-  override def advance(): Boolean = maybeIterator.exists(_.hasNext)
+  override def advance(): Boolean = maybeIterator match {
+    case Some(iterator) if iterator.hasNext =>
+      current = Some(iterator.next())
+      recordsReturned += 1
+      true
+    case _ =>
+      false
+  }
 
-  override def getCurrent: Document =
-    maybeIterator
-      .filter(_.hasNext)
-      // .map(iterator => new Document(iterator.next()))
-      .map(_.next())
-      .orNull
+  override def getCurrent: Document = current.orNull
 
   override def getCurrentSource: CosmosDbBoundedSource = cosmosSource
 
-  override def close(): Unit = maybeClient.foreach(_.close())
+  override def close(): Unit = {
+    log.info("Closing reader after reading {} records.", recordsReturned)
+    maybeClient.foreach(_.close())
+    maybeClient = None
+    maybeIterator = None
+  }
 }
diff --git a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedSource.scala b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedSource.scala
index 2e195a5ab5..7ad008cb1e 100644
--- a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedSource.scala
+++ b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbBoundedSource.scala
@@ -16,9 +16,8 @@
 
 package com.spotify.scio.cosmosdb.read
 
-import org.apache.beam.sdk.annotations.Experimental
-import org.apache.beam.sdk.annotations.Experimental.Kind
-import org.apache.beam.sdk.coders.{Coder, SerializableCoder}
+import com.spotify.scio.annotations.experimental
+import org.apache.beam.sdk.coders.{ Coder, SerializableCoder }
 import org.apache.beam.sdk.io.BoundedSource
 import org.apache.beam.sdk.options.PipelineOptions
 import org.bson.Document
@@ -29,7 +28,7 @@ import java.util.Collections
 /**
  * A CosmosDB Core (SQL) API [[BoundedSource]] reading [[Document]] from a given instance.
  */
-@Experimental(Kind.SOURCE_SINK)
+@experimental
 private[read] class CosmosDbBoundedSource(private[read] val readCosmos: CosmosDbRead)
     extends BoundedSource[Document] {
 
diff --git a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbRead.scala b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbRead.scala
index 73b454f549..9e894f8716 100644
--- a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbRead.scala
+++ b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/read/CosmosDbRead.scala
@@ -16,42 +16,29 @@
 
 package com.spotify.scio.cosmosdb.read
 
-import org.apache.beam.sdk.annotations.Experimental
-import org.apache.beam.sdk.annotations.Experimental.Kind
+import com.spotify.scio.annotations.experimental
 import org.apache.beam.sdk.io.Read
 import org.apache.beam.sdk.transforms.PTransform
-import org.apache.beam.sdk.values.{PBegin, PCollection}
+import org.apache.beam.sdk.values.{ PBegin, PCollection }
 import org.bson.Document
 import org.slf4j.LoggerFactory
 
 /** A [[PTransform]] to read data from CosmosDB Core (SQL) API. */
-@Experimental(Kind.SOURCE_SINK)
+@experimental
 private[cosmosdb] case class CosmosDbRead(
-  endpoint: String = null,
-  key: String = null,
-  database: String = null,
-  container: String = null,
+  endpoint: String,
+  key: String,
+  database: String,
+  container: String,
   query: String = null
 ) extends PTransform[PBegin, PCollection[Document]] {
 
   private val log = LoggerFactory.getLogger(classOf[CosmosDbRead])
 
-  /** Create new ReadCosmos based into previous ReadCosmos, modifying the endpoint */
-  def withCosmosEndpoint(endpoint: String): CosmosDbRead = this.copy(endpoint = endpoint)
-
-  def withCosmosKey(key: String): CosmosDbRead = this.copy(key = key)
-
-  def withDatabase(database: String): CosmosDbRead = this.copy(database = database)
-
-  def withQuery(query: String): CosmosDbRead = this.copy(query = query)
-
-  def withContainer(container: String): CosmosDbRead = this.copy(container = container)
-
   override def expand(input: PBegin): PCollection[Document] = {
     log.debug(s"Read CosmosDB with endpoint: $endpoint and query: $query")
     validate()
 
-    // input.getPipeline.apply(Read.from(new CosmosSource(this)))
     input.apply(Read.from(new CosmosDbBoundedSource(this)))
   }
 
diff --git a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/syntax/ScioContextSyntax.scala b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/syntax/ScioContextSyntax.scala
index c27aaf3064..cebd59c407 100644
--- a/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/syntax/ScioContextSyntax.scala
+++ b/scio-cosmosdb/src/main/scala/com/spotify/scio/cosmosdb/syntax/ScioContextSyntax.scala
@@ -17,6 +17,7 @@
 package com.spotify.scio.cosmosdb.syntax
 
 import com.spotify.scio.ScioContext
+import com.spotify.scio.annotations.experimental
 import com.spotify.scio.cosmosdb.ReadCosmosDdIO
 import com.spotify.scio.values.SCollection
 import org.bson.Document
@@ -28,6 +29,7 @@ trait ScioContextSyntax {
 
 final class CosmosDbScioContextOps(private val sc: ScioContext) extends AnyVal {
 
+  @experimental
   /**
    * Read data from CosmosDB CORE (SQL) API
    *