diff --git a/akka-stream/src/main/boilerplate/akka/stream/scaladsl/GraphApply.scala.template b/akka-stream/src/main/boilerplate/akka/stream/scaladsl/GraphApply.scala.template
index 327b7f04b3..0f811c7f09 100644
--- a/akka-stream/src/main/boilerplate/akka/stream/scaladsl/GraphApply.scala.template
+++ b/akka-stream/src/main/boilerplate/akka/stream/scaladsl/GraphApply.scala.template
@@ -58,8 +58,8 @@ trait GraphApply {
 /**
  * INTERNAL API
  */
-private[stream] object GraphApply {
-  final class GraphImpl[S <: Shape, Mat](override val shape: S, private[stream] override val module: StreamLayout.Module)
+object GraphApply {
+  final class GraphImpl[S <: Shape, Mat](override val shape: S, override val module: StreamLayout.Module)
     extends Graph[S, Mat] {
     
     override def toString: String = s"Graph($shape, $module)"
@@ -70,3 +70,15 @@ private[stream] object GraphApply {
     override def named(name: String): Graph[S, Mat] = withAttributes(Attributes.name(name))
   }
 }
+
+/**
+ * INTERNAL API
+ */
+object ModuleExtractor {
+  def unapply[S <: Shape, Mat](graph: Graph[S, Mat]): Option[Module] = graph match {
+    case module: Module =>
+      Some(module)
+    case _ =>
+      None
+  }
+}
diff --git a/akka-stream/src/main/boilerplate/akka/stream/scaladsl/ZipWithApply.scala.template b/akka-stream/src/main/boilerplate/akka/stream/scaladsl/ZipWithApply.scala.template
index c53b30f20c..b4824c26d3 100644
--- a/akka-stream/src/main/boilerplate/akka/stream/scaladsl/ZipWithApply.scala.template
+++ b/akka-stream/src/main/boilerplate/akka/stream/scaladsl/ZipWithApply.scala.template
@@ -23,7 +23,7 @@ trait ZipWithApply {
 }
 
 [2..20#/** `ZipWith` specialized for 1 inputs */
-class ZipWith1[[#A1#], O] (zipper: ([#A1#]) ⇒ O) extends GraphStage[FanInShape1[[#A1#], O]] {
+class ZipWith1[[#A1#], O] (val zipper: ([#A1#]) ⇒ O) extends GraphStage[FanInShape1[[#A1#], O]] {
   override def initialAttributes = Attributes.name("ZipWith1")
   override val shape: FanInShape1[[#A1#], O] = new FanInShape1[[#A1#], O]("ZipWith1")
   def out: Outlet[O] = shape.out
diff --git a/akka-stream/src/main/scala/akka/stream/Attributes.scala b/akka-stream/src/main/scala/akka/stream/Attributes.scala
index e46a53c356..7f1c7d192f 100644
--- a/akka-stream/src/main/scala/akka/stream/Attributes.scala
+++ b/akka-stream/src/main/scala/akka/stream/Attributes.scala
@@ -143,7 +143,7 @@ final case class Attributes(attributeList: List[Attributes.Attribute] = Nil) {
   /**
    * INTERNAL API
    */
-  private[akka] def nameOrDefault(default: String = "unknown-operation"): String = {
+  def nameOrDefault(default: String = "unknown-operation"): String = {
     @tailrec def concatNames(i: Iterator[Attribute], first: String, buf: StringBuilder): String =
       if (i.hasNext)
         i.next() match {
@@ -187,7 +187,7 @@ object Attributes {
   /**
    * INTERNAL API
    */
-  private[akka] def apply(attribute: Attribute): Attributes =
+  def apply(attribute: Attribute): Attributes =
     apply(List(attribute))
 
   val none: Attributes = Attributes()
diff --git a/akka-stream/src/main/scala/akka/stream/impl/ActorMaterializerImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/ActorMaterializerImpl.scala
index a3eb77d2f1..8bcda5503c 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/ActorMaterializerImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/ActorMaterializerImpl.scala
@@ -42,7 +42,32 @@ abstract class ExtendedActorMaterializer extends ActorMaterializer {
   /**
    * INTERNAL API
    */
-  def actorOf(context: MaterializationContext, props: Props): ActorRef
+  override def actorOf(context: MaterializationContext, props: Props): ActorRef = {
+    val dispatcher =
+      if (props.deploy.dispatcher == Deploy.NoDispatcherGiven) effectiveSettings(context.effectiveAttributes).dispatcher
+      else props.dispatcher
+    actorOf(props, context.stageName, dispatcher)
+  }
+
+  /**
+   * INTERNAL API
+   */
+  protected def actorOf(props: Props, name: String, dispatcher: String): ActorRef = {
+    supervisor match {
+      case ref: LocalActorRef ⇒
+        ref.underlying.attachChild(props.withDispatcher(dispatcher), name, systemService = false)
+      case ref: RepointableActorRef ⇒
+        if (ref.isStarted)
+          ref.underlying.asInstanceOf[ActorCell].attachChild(props.withDispatcher(dispatcher), name, systemService = false)
+        else {
+          implicit val timeout = ref.system.settings.CreationTimeout
+          val f = (supervisor ? StreamSupervisor.Materialize(props.withDispatcher(dispatcher), name)).mapTo[ActorRef]
+          Await.result(f, timeout.duration)
+        }
+      case unknown ⇒
+        throw new IllegalStateException(s"Stream supervisor must be a local actor, was [${unknown.getClass.getName}]")
+    }
+  }
 
   /**
    * INTERNAL API
@@ -220,30 +245,6 @@ private[akka] case class ActorMaterializerImpl(
     case other                    ⇒ other
   })
 
-  override def actorOf(context: MaterializationContext, props: Props): ActorRef = {
-    val dispatcher =
-      if (props.deploy.dispatcher == Deploy.NoDispatcherGiven) effectiveSettings(context.effectiveAttributes).dispatcher
-      else props.dispatcher
-    actorOf(props, context.stageName, dispatcher)
-  }
-
-  private[akka] def actorOf(props: Props, name: String, dispatcher: String): ActorRef = {
-    supervisor match {
-      case ref: LocalActorRef ⇒
-        ref.underlying.attachChild(props.withDispatcher(dispatcher), name, systemService = false)
-      case ref: RepointableActorRef ⇒
-        if (ref.isStarted)
-          ref.underlying.asInstanceOf[ActorCell].attachChild(props.withDispatcher(dispatcher), name, systemService = false)
-        else {
-          implicit val timeout = ref.system.settings.CreationTimeout
-          val f = (supervisor ? StreamSupervisor.Materialize(props.withDispatcher(dispatcher), name)).mapTo[ActorRef]
-          Await.result(f, timeout.duration)
-        }
-      case unknown ⇒
-        throw new IllegalStateException(s"Stream supervisor must be a local actor, was [${unknown.getClass.getName}]")
-    }
-  }
-
 }
 
 private[akka] class SubFusingActorMaterializerImpl(val delegate: ExtendedActorMaterializer, registerShell: GraphInterpreterShell ⇒ ActorRef) extends Materializer {
@@ -263,7 +264,7 @@ private[akka] class SubFusingActorMaterializerImpl(val delegate: ExtendedActorMa
 /**
  * INTERNAL API
  */
-private[akka] object FlowNames extends ExtensionId[FlowNames] with ExtensionIdProvider {
+object FlowNames extends ExtensionId[FlowNames] with ExtensionIdProvider {
   override def get(system: ActorSystem): FlowNames = super.get(system)
   override def lookup() = FlowNames
   override def createExtension(system: ExtendedActorSystem): FlowNames = new FlowNames
@@ -272,14 +273,14 @@ private[akka] object FlowNames extends ExtensionId[FlowNames] with ExtensionIdPr
 /**
  * INTERNAL API
  */
-private[akka] class FlowNames extends Extension {
+class FlowNames extends Extension {
   val name = SeqActorName("Flow")
 }
 
 /**
  * INTERNAL API
  */
-private[akka] object StreamSupervisor {
+object StreamSupervisor {
   def props(settings: ActorMaterializerSettings, haveShutDown: AtomicBoolean): Props =
     Props(new StreamSupervisor(settings, haveShutDown)).withDeploy(Deploy.local)
 
@@ -301,7 +302,7 @@ private[akka] object StreamSupervisor {
   case object PrintDebugDump
 }
 
-private[akka] class StreamSupervisor(settings: ActorMaterializerSettings, haveShutDown: AtomicBoolean) extends Actor {
+class StreamSupervisor(settings: ActorMaterializerSettings, haveShutDown: AtomicBoolean) extends Actor {
   import akka.stream.impl.StreamSupervisor._
 
   override def supervisorStrategy = SupervisorStrategy.stoppingStrategy
diff --git a/akka-stream/src/main/scala/akka/stream/impl/ActorPublisher.scala b/akka-stream/src/main/scala/akka/stream/impl/ActorPublisher.scala
index 42d90c4d1c..65b5675b36 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/ActorPublisher.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/ActorPublisher.scala
@@ -14,7 +14,7 @@ import org.reactivestreams.Subscription
 /**
  * INTERNAL API
  */
-private[akka] object ActorPublisher {
+object ActorPublisher {
   val NormalShutdownReasonMessage = "Cannot subscribe to shut-down Publisher"
   class NormalShutdownException extends IllegalStateException(NormalShutdownReasonMessage) with NoStackTrace
   val NormalShutdownReason: Throwable = new NormalShutdownException
@@ -35,7 +35,7 @@ private[akka] object ActorPublisher {
  * When you instantiate this class, or its subclasses, you MUST send an ExposedPublisher message to the wrapped
  * ActorRef! If you don't need to subclass, prefer the apply() method on the companion object which takes care of this.
  */
-private[akka] class ActorPublisher[T](val impl: ActorRef) extends Publisher[T] {
+class ActorPublisher[T](val impl: ActorRef) extends Publisher[T] {
   import ReactiveStreamsCompliance._
 
   // The subscriber of an subscription attempt is first placed in this list of pending subscribers.
diff --git a/akka-stream/src/main/scala/akka/stream/impl/FanIn.scala b/akka-stream/src/main/scala/akka/stream/impl/FanIn.scala
index 12d89f459e..822c1e6b13 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/FanIn.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/FanIn.scala
@@ -11,14 +11,14 @@ import org.reactivestreams.{ Subscription, Subscriber }
 /**
  * INTERNAL API
  */
-private[akka] object FanIn {
+object FanIn {
 
   final case class OnError(id: Int, cause: Throwable) extends DeadLetterSuppression with NoSerializationVerificationNeeded
   final case class OnComplete(id: Int) extends DeadLetterSuppression with NoSerializationVerificationNeeded
   final case class OnNext(id: Int, e: Any) extends DeadLetterSuppression with NoSerializationVerificationNeeded
   final case class OnSubscribe(id: Int, subscription: Subscription) extends DeadLetterSuppression with NoSerializationVerificationNeeded
 
-  private[akka] final case class SubInput[T](impl: ActorRef, id: Int) extends Subscriber[T] {
+  final case class SubInput[T](impl: ActorRef, id: Int) extends Subscriber[T] {
     override def onError(cause: Throwable): Unit = {
       ReactiveStreamsCompliance.requireNonNullException(cause)
       impl ! OnError(id, cause)
@@ -252,7 +252,7 @@ private[akka] object FanIn {
 /**
  * INTERNAL API
  */
-private[akka] abstract class FanIn(val settings: ActorMaterializerSettings, val inputCount: Int) extends Actor with ActorLogging with Pump {
+abstract class FanIn(val settings: ActorMaterializerSettings, val inputCount: Int) extends Actor with ActorLogging with Pump {
   import FanIn._
 
   protected val primaryOutputs: Outputs = new SimpleOutputs(self, this)
diff --git a/akka-stream/src/main/scala/akka/stream/impl/FanOut.scala b/akka-stream/src/main/scala/akka/stream/impl/FanOut.scala
index 82b5e57f8c..b61e82d0f1 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/FanOut.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/FanOut.scala
@@ -12,7 +12,7 @@ import org.reactivestreams.Subscription
 /**
  * INTERNAL API
  */
-private[akka] object FanOut {
+object FanOut {
 
   final case class SubstreamRequestMore(id: Int, demand: Long) extends DeadLetterSuppression with NoSerializationVerificationNeeded
   final case class SubstreamCancel(id: Int) extends DeadLetterSuppression with NoSerializationVerificationNeeded
@@ -247,7 +247,7 @@ private[akka] object FanOut {
 /**
  * INTERNAL API
  */
-private[akka] abstract class FanOut(val settings: ActorMaterializerSettings, val outputCount: Int) extends Actor with ActorLogging with Pump {
+abstract class FanOut(val settings: ActorMaterializerSettings, val outputCount: Int) extends Actor with ActorLogging with Pump {
   import FanOut._
 
   protected val outputBunch = new OutputBunch(outputCount, self, this)
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Modules.scala b/akka-stream/src/main/scala/akka/stream/impl/Modules.scala
index 21afc53aa4..76eefcffb6 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Modules.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Modules.scala
@@ -15,7 +15,7 @@ import akka.event.Logging
 /**
  * INTERNAL API
  */
-private[akka] abstract class SourceModule[+Out, +Mat](val shape: SourceShape[Out]) extends AtomicModule {
+abstract class SourceModule[+Out, +Mat](val shape: SourceShape[Out]) extends AtomicModule {
 
   protected def label: String = Logging.simpleName(this)
   final override def toString: String = f"$label [${System.identityHashCode(this)}%08x]"
@@ -45,7 +45,7 @@ private[akka] abstract class SourceModule[+Out, +Mat](val shape: SourceShape[Out
  * Holds a `Subscriber` representing the input side of the flow.
  * The `Subscriber` can later be connected to an upstream `Publisher`.
  */
-private[akka] final class SubscriberSource[Out](val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, Subscriber[Out]](shape) {
+final class SubscriberSource[Out](val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, Subscriber[Out]](shape) {
 
   override def create(context: MaterializationContext): (Publisher[Out], Subscriber[Out]) = {
     val processor = new VirtualProcessor[Out]
@@ -63,7 +63,7 @@ private[akka] final class SubscriberSource[Out](val attributes: Attributes, shap
  * that mediate the flow of elements downstream and the propagation of
  * back-pressure upstream.
  */
-private[akka] final class PublisherSource[Out](p: Publisher[Out], val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, NotUsed](shape) {
+final class PublisherSource[Out](p: Publisher[Out], val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, NotUsed](shape) {
 
   override protected def label: String = s"PublisherSource($p)"
 
@@ -76,7 +76,7 @@ private[akka] final class PublisherSource[Out](p: Publisher[Out], val attributes
 /**
  * INTERNAL API
  */
-private[akka] final class MaybeSource[Out](val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, Promise[Option[Out]]](shape) {
+final class MaybeSource[Out](val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, Promise[Option[Out]]](shape) {
 
   override def create(context: MaterializationContext) = {
     val p = Promise[Option[Out]]()
@@ -91,7 +91,7 @@ private[akka] final class MaybeSource[Out](val attributes: Attributes, shape: So
  * Creates and wraps an actor into [[org.reactivestreams.Publisher]] from the given `props`,
  * which should be [[akka.actor.Props]] for an [[akka.stream.actor.ActorPublisher]].
  */
-private[akka] final class ActorPublisherSource[Out](props: Props, val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, ActorRef](shape) {
+final class ActorPublisherSource[Out](props: Props, val attributes: Attributes, shape: SourceShape[Out]) extends SourceModule[Out, ActorRef](shape) {
 
   override def create(context: MaterializationContext) = {
     val publisherRef = ActorMaterializerHelper.downcast(context.materializer).actorOf(context, props)
@@ -106,7 +106,7 @@ private[akka] final class ActorPublisherSource[Out](props: Props, val attributes
 /**
  * INTERNAL API
  */
-private[akka] final class ActorRefSource[Out](
+final class ActorRefSource[Out](
   bufferSize: Int, overflowStrategy: OverflowStrategy, val attributes: Attributes, shape: SourceShape[Out])
   extends SourceModule[Out, ActorRef](shape) {
 
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala b/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
index 60fcee909b..d2f62f25bc 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
@@ -38,7 +38,7 @@ import akka.event.Logging
 /**
  * INTERNAL API
  */
-private[akka] abstract class SinkModule[-In, Mat](val shape: SinkShape[In]) extends AtomicModule {
+abstract class SinkModule[-In, Mat](val shape: SinkShape[In]) extends AtomicModule {
 
   /**
    * Create the Subscriber or VirtualPublisher that consumes the incoming
@@ -125,7 +125,7 @@ private[akka] final class FanoutPublisherSink[In](
  * Attaches a subscriber to this stream which will just discard all received
  * elements.
  */
-private[akka] final class SinkholeSink(val attributes: Attributes, shape: SinkShape[Any]) extends SinkModule[Any, Future[Done]](shape) {
+final class SinkholeSink(val attributes: Attributes, shape: SinkShape[Any]) extends SinkModule[Any, Future[Done]](shape) {
 
   override def create(context: MaterializationContext) = {
     val effectiveSettings = ActorMaterializerHelper.downcast(context.materializer).effectiveSettings(context.effectiveAttributes)
@@ -141,7 +141,7 @@ private[akka] final class SinkholeSink(val attributes: Attributes, shape: SinkSh
  * INTERNAL API
  * Attaches a subscriber to this stream.
  */
-private[akka] final class SubscriberSink[In](subscriber: Subscriber[In], val attributes: Attributes, shape: SinkShape[In]) extends SinkModule[In, NotUsed](shape) {
+final class SubscriberSink[In](subscriber: Subscriber[In], val attributes: Attributes, shape: SinkShape[In]) extends SinkModule[In, NotUsed](shape) {
 
   override def create(context: MaterializationContext) = (subscriber, NotUsed)
 
@@ -153,7 +153,7 @@ private[akka] final class SubscriberSink[In](subscriber: Subscriber[In], val att
  * INTERNAL API
  * A sink that immediately cancels its upstream upon materialization.
  */
-private[akka] final class CancelSink(val attributes: Attributes, shape: SinkShape[Any]) extends SinkModule[Any, NotUsed](shape) {
+final class CancelSink(val attributes: Attributes, shape: SinkShape[Any]) extends SinkModule[Any, NotUsed](shape) {
   override def create(context: MaterializationContext): (Subscriber[Any], NotUsed) = (new CancellingSubscriber[Any], NotUsed)
   override protected def newInstance(shape: SinkShape[Any]): SinkModule[Any, NotUsed] = new CancelSink(attributes, shape)
   override def withAttributes(attr: Attributes): AtomicModule = new CancelSink(attr, amendShape(attr))
@@ -164,7 +164,7 @@ private[akka] final class CancelSink(val attributes: Attributes, shape: SinkShap
  * Creates and wraps an actor into [[org.reactivestreams.Subscriber]] from the given `props`,
  * which should be [[akka.actor.Props]] for an [[akka.stream.actor.ActorSubscriber]].
  */
-private[akka] final class ActorSubscriberSink[In](props: Props, val attributes: Attributes, shape: SinkShape[In]) extends SinkModule[In, ActorRef](shape) {
+final class ActorSubscriberSink[In](props: Props, val attributes: Attributes, shape: SinkShape[In]) extends SinkModule[In, ActorRef](shape) {
 
   override def create(context: MaterializationContext) = {
     val subscriberRef = ActorMaterializerHelper.downcast(context.materializer).actorOf(context, props)
@@ -178,9 +178,9 @@ private[akka] final class ActorSubscriberSink[In](props: Props, val attributes:
 /**
  * INTERNAL API
  */
-private[akka] final class ActorRefSink[In](ref: ActorRef, onCompleteMessage: Any,
-                                           val attributes: Attributes,
-                                           shape:          SinkShape[In]) extends SinkModule[In, NotUsed](shape) {
+final class ActorRefSink[In](ref: ActorRef, onCompleteMessage: Any,
+                             val attributes: Attributes,
+                             shape:          SinkShape[In]) extends SinkModule[In, NotUsed](shape) {
 
   override def create(context: MaterializationContext) = {
     val actorMaterializer = ActorMaterializerHelper.downcast(context.materializer)
@@ -197,7 +197,7 @@ private[akka] final class ActorRefSink[In](ref: ActorRef, onCompleteMessage: Any
     new ActorRefSink[In](ref, onCompleteMessage, attr, amendShape(attr))
 }
 
-private[akka] final class LastOptionStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[Option[T]]] {
+final class LastOptionStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[Option[T]]] {
 
   val in: Inlet[T] = Inlet("lastOption.in")
 
@@ -234,7 +234,7 @@ private[akka] final class LastOptionStage[T] extends GraphStageWithMaterializedV
   override def toString: String = "LastOptionStage"
 }
 
-private[akka] final class HeadOptionStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[Option[T]]] {
+final class HeadOptionStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[Option[T]]] {
 
   val in: Inlet[T] = Inlet("headOption.in")
 
@@ -266,7 +266,7 @@ private[akka] final class HeadOptionStage[T] extends GraphStageWithMaterializedV
   override def toString: String = "HeadOptionStage"
 }
 
-private[akka] final class SeqStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[immutable.Seq[T]]] {
+final class SeqStage[T] extends GraphStageWithMaterializedValue[SinkShape[T], Future[immutable.Seq[T]]] {
   val in = Inlet[T]("seq.in")
 
   override def toString: String = "SeqStage"
@@ -315,7 +315,7 @@ private[stream] object QueueSink {
 /**
  * INTERNAL API
  */
-final private[stream] class QueueSink[T]() extends GraphStageWithMaterializedValue[SinkShape[T], SinkQueueWithCancel[T]] {
+final class QueueSink[T]() extends GraphStageWithMaterializedValue[SinkShape[T], SinkQueueWithCancel[T]] {
   type Requested[E] = Promise[Option[E]]
 
   val in = Inlet[T]("queueSink.in")
@@ -406,7 +406,7 @@ final private[stream] class QueueSink[T]() extends GraphStageWithMaterializedVal
   }
 }
 
-private[akka] final class SinkQueueAdapter[T](delegate: SinkQueueWithCancel[T]) extends akka.stream.javadsl.SinkQueueWithCancel[T] {
+final class SinkQueueAdapter[T](delegate: SinkQueueWithCancel[T]) extends akka.stream.javadsl.SinkQueueWithCancel[T] {
   import akka.dispatch.ExecutionContexts.{ sameThreadExecutionContext ⇒ same }
   def pull(): CompletionStage[Optional[T]] = delegate.pull().map(_.asJava)(same).toJava
   def cancel(): Unit = delegate.cancel()
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Sources.scala b/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
index 326d6f283f..c8a36c2323 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
@@ -31,7 +31,7 @@ private[stream] object QueueSource {
 /**
  * INTERNAL API
  */
-final private[stream] class QueueSource[T](maxBuffer: Int, overflowStrategy: OverflowStrategy) extends GraphStageWithMaterializedValue[SourceShape[T], SourceQueueWithComplete[T]] {
+final class QueueSource[T](maxBuffer: Int, overflowStrategy: OverflowStrategy) extends GraphStageWithMaterializedValue[SourceShape[T], SourceQueueWithComplete[T]] {
   import QueueSource._
 
   val out = Outlet[T]("queueSource.out")
@@ -185,7 +185,7 @@ final private[stream] class QueueSource[T](maxBuffer: Int, overflowStrategy: Ove
   }
 }
 
-private[akka] final class SourceQueueAdapter[T](delegate: SourceQueueWithComplete[T]) extends akka.stream.javadsl.SourceQueueWithComplete[T] {
+final class SourceQueueAdapter[T](delegate: SourceQueueWithComplete[T]) extends akka.stream.javadsl.SourceQueueWithComplete[T] {
   def offer(elem: T): CompletionStage[QueueOfferResult] = delegate.offer(elem).toJava
   def watchCompletion(): CompletionStage[Done] = delegate.watchCompletion().toJava
   def complete(): Unit = delegate.complete()
@@ -195,7 +195,7 @@ private[akka] final class SourceQueueAdapter[T](delegate: SourceQueueWithComplet
 /**
  * INTERNAL API
  */
-private[stream] final class UnfoldResourceSource[T, S](
+final class UnfoldResourceSource[T, S](
   create:   () ⇒ S,
   readData: (S) ⇒ Option[T],
   close:    (S) ⇒ Unit) extends GraphStage[SourceShape[T]] {
@@ -252,7 +252,7 @@ private[stream] final class UnfoldResourceSource[T, S](
   override def toString = "UnfoldResourceSource"
 }
 
-private[stream] final class UnfoldResourceSourceAsync[T, S](
+final class UnfoldResourceSourceAsync[T, S](
   create:   () ⇒ Future[S],
   readData: (S) ⇒ Future[Option[T]],
   close:    (S) ⇒ Future[Done]) extends GraphStage[SourceShape[T]] {
@@ -332,4 +332,4 @@ private[stream] final class UnfoldResourceSourceAsync[T, S](
   }
   override def toString = "UnfoldResourceSourceAsync"
 
-}
\ No newline at end of file
+}
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Stages.scala b/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
index 4ae0ab8bd4..a3d9ed72da 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
@@ -18,7 +18,7 @@ import scala.collection.immutable
 /**
  * INTERNAL API
  */
-private[stream] object Stages {
+object Stages {
 
   object DefaultAttributes {
     val IODispatcher = ActorAttributes.Dispatcher("akka.stream.default-blocking-io-dispatcher")
diff --git a/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala b/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
index 41128e3ad5..80ba1c2bae 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
@@ -1004,7 +1004,7 @@ abstract class MaterializerSession(val topLevel: StreamLayout.Module, val initia
 /**
  * INTERNAL API
  */
-private[akka] final case class ProcessorModule[In, Out, Mat](
+final case class ProcessorModule[In, Out, Mat](
   val createProcessor: () ⇒ (Processor[In, Out], Mat),
   attributes:          Attributes                     = DefaultAttributes.processor) extends StreamLayout.AtomicModule {
   val inPort = Inlet[In]("ProcessorModule.in")
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Throttle.scala b/akka-stream/src/main/scala/akka/stream/impl/Throttle.scala
index 54a740cff4..577ea899e0 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Throttle.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Throttle.scala
@@ -14,7 +14,7 @@ import scala.concurrent.duration.{ FiniteDuration, _ }
 /**
  * INTERNAL API
  */
-private[stream] class Throttle[T](
+class Throttle[T](
   cost:            Int,
   per:             FiniteDuration,
   maximumBurst:    Int,
@@ -84,4 +84,4 @@ private[stream] class Throttle[T](
   }
 
   override def toString = "Throttle"
-}
\ No newline at end of file
+}
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Timers.scala b/akka-stream/src/main/scala/akka/stream/impl/Timers.scala
index 8f6ad1081a..daa0fea687 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Timers.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Timers.scala
@@ -23,7 +23,7 @@ import scala.concurrent.duration.{ Duration, FiniteDuration }
  *  - if the timer fires before the event happens, these stages all fail the stream
  *  - otherwise, these streams do not interfere with the element flow, ordinary completion or failure
  */
-private[stream] object Timers {
+object Timers {
   private def idleTimeoutCheckInterval(timeout: FiniteDuration): FiniteDuration = {
     import scala.concurrent.duration._
     FiniteDuration(
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Unfold.scala b/akka-stream/src/main/scala/akka/stream/impl/Unfold.scala
index dd5358cbd8..e60c810079 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Unfold.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Unfold.scala
@@ -13,7 +13,7 @@ import scala.util.{ Failure, Success, Try }
 /**
  * INTERNAL API
  */
-private[akka] final class Unfold[S, E](s: S, f: S ⇒ Option[(S, E)]) extends GraphStage[SourceShape[E]] {
+final class Unfold[S, E](s: S, f: S ⇒ Option[(S, E)]) extends GraphStage[SourceShape[E]] {
   val out: Outlet[E] = Outlet("Unfold.out")
   override val shape: SourceShape[E] = SourceShape(out)
   override def initialAttributes: Attributes = DefaultAttributes.unfold
@@ -36,7 +36,7 @@ private[akka] final class Unfold[S, E](s: S, f: S ⇒ Option[(S, E)]) extends Gr
 /**
  * INTERNAL API
  */
-private[akka] final class UnfoldAsync[S, E](s: S, f: S ⇒ Future[Option[(S, E)]]) extends GraphStage[SourceShape[E]] {
+final class UnfoldAsync[S, E](s: S, f: S ⇒ Future[Option[(S, E)]]) extends GraphStage[SourceShape[E]] {
   val out: Outlet[E] = Outlet("UnfoldAsync.out")
   override val shape: SourceShape[E] = SourceShape(out)
   override def initialAttributes: Attributes = DefaultAttributes.unfoldAsync
diff --git a/akka-stream/src/main/scala/akka/stream/impl/fusing/ActorGraphInterpreter.scala b/akka-stream/src/main/scala/akka/stream/impl/fusing/ActorGraphInterpreter.scala
index d50078b098..3b14652c29 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/fusing/ActorGraphInterpreter.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/fusing/ActorGraphInterpreter.scala
@@ -22,8 +22,8 @@ import scala.util.control.NonFatal
 /**
  * INTERNAL API
  */
-private[stream] final case class GraphModule(assembly: GraphAssembly, shape: Shape, attributes: Attributes,
-                                             matValIDs: Array[Module]) extends AtomicModule {
+final case class GraphModule(assembly: GraphAssembly, shape: Shape, attributes: Attributes,
+                             matValIDs: Array[Module]) extends AtomicModule {
 
   override def withAttributes(newAttr: Attributes): Module = copy(attributes = newAttr)
 
@@ -44,7 +44,7 @@ private[stream] final case class GraphModule(assembly: GraphAssembly, shape: Sha
 /**
  * INTERNAL API
  */
-private[stream] object ActorGraphInterpreter {
+object ActorGraphInterpreter {
   trait BoundaryEvent extends DeadLetterSuppression with NoSerializationVerificationNeeded {
     def shell: GraphInterpreterShell
   }
@@ -526,7 +526,7 @@ final class GraphInterpreterShell(
 /**
  * INTERNAL API
  */
-private[stream] class ActorGraphInterpreter(_initial: GraphInterpreterShell) extends Actor with ActorLogging {
+class ActorGraphInterpreter(_initial: GraphInterpreterShell) extends Actor with ActorLogging {
   import ActorGraphInterpreter._
 
   var activeInterpreters = Set.empty[GraphInterpreterShell]
diff --git a/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphInterpreter.scala b/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphInterpreter.scala
index 217f50c2fe..da05746a19 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphInterpreter.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphInterpreter.scala
@@ -21,7 +21,7 @@ import akka.stream.impl.fusing.GraphStages.MaterializedValueSource
  *
  * (See the class for the documentation of the internals)
  */
-private[akka] object GraphInterpreter {
+object GraphInterpreter {
   /**
    * Compile time constant, enable it for debug logging to the console.
    */
@@ -346,7 +346,7 @@ private[akka] object GraphInterpreter {
  * be modeled, or even dissolved (if preempted and a "stealing" external event is injected; for example the non-cycle
  * edge of a balance is pulled, dissolving the original cycle).
  */
-private[stream] final class GraphInterpreter(
+final class GraphInterpreter(
   private val assembly: GraphInterpreter.GraphAssembly,
   val materializer:     Materializer,
   val log:              LoggingAdapter,
diff --git a/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphStages.scala b/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphStages.scala
index aa5d0bd6f4..4e2fe7e682 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphStages.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/fusing/GraphStages.scala
@@ -25,7 +25,7 @@ import scala.util.Try
 /**
  * INTERNAL API
  */
-private[akka] final case class GraphStageModule(
+final case class GraphStageModule(
   shape:      Shape,
   attributes: Attributes,
   stage:      GraphStageWithMaterializedValue[Shape, Any]) extends AtomicModule {
@@ -50,7 +50,7 @@ object GraphStages {
   /**
    * INTERNAL API
    */
-  private[akka] abstract class SimpleLinearGraphStage[T] extends GraphStage[FlowShape[T, T]] {
+  abstract class SimpleLinearGraphStage[T] extends GraphStage[FlowShape[T, T]] {
     val in = Inlet[T](Logging.simpleName(this) + ".in")
     val out = Outlet[T](Logging.simpleName(this) + ".out")
     override val shape = FlowShape(in, out)
@@ -77,7 +77,7 @@ object GraphStages {
   /**
    * INTERNAL API
    */
-  private[stream] final class Detacher[T] extends GraphStage[FlowShape[T, T]] {
+  final class Detacher[T] extends GraphStage[FlowShape[T, T]] {
     val in = Inlet[T]("Detacher.in")
     val out = Outlet[T]("Detacher.out")
     override def initialAttributes = DefaultAttributes.detacher
@@ -288,7 +288,7 @@ object GraphStages {
     override def toString: String = s"MaterializedValueSource($computation)"
   }
 
-  private[stream] final class SingleSource[T](val elem: T) extends GraphStage[SourceShape[T]] {
+  final class SingleSource[T](val elem: T) extends GraphStage[SourceShape[T]] {
     override def initialAttributes: Attributes = DefaultAttributes.singleSource
     ReactiveStreamsCompliance.requireNonNullElement(elem)
     val out = Outlet[T]("single.out")
@@ -304,7 +304,7 @@ object GraphStages {
     override def toString: String = s"SingleSource($elem)"
   }
 
-  private[stream] final class FutureSource[T](val future: Future[T]) extends GraphStage[SourceShape[T]] {
+  final class FutureSource[T](val future: Future[T]) extends GraphStage[SourceShape[T]] {
     ReactiveStreamsCompliance.requireNonNullElement(future)
     val shape = SourceShape(Outlet[T]("future.out"))
     val out = shape.out
diff --git a/akka-stream/src/main/scala/akka/stream/impl/fusing/Ops.scala b/akka-stream/src/main/scala/akka/stream/impl/fusing/Ops.scala
index 30cd433fb5..32e64cc9d1 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/fusing/Ops.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/fusing/Ops.scala
@@ -25,7 +25,7 @@ import akka.stream.impl.Stages.DefaultAttributes
 /**
  * INTERNAL API
  */
-private[akka] final case class Map[In, Out](f: In ⇒ Out, decider: Supervision.Decider) extends PushStage[In, Out] {
+final case class Map[In, Out](f: In ⇒ Out, decider: Supervision.Decider) extends PushStage[In, Out] {
   override def onPush(elem: In, ctx: Context[Out]): SyncDirective = ctx.push(f(elem))
 
   override def decide(t: Throwable): Supervision.Directive = decider(t)
@@ -34,7 +34,7 @@ private[akka] final case class Map[In, Out](f: In ⇒ Out, decider: Supervision.
 /**
  * INTERNAL API
  */
-private[akka] final case class Filter[T](p: T ⇒ Boolean) extends SimpleLinearGraphStage[T] {
+final case class Filter[T](p: T ⇒ Boolean) extends SimpleLinearGraphStage[T] {
   override def initialAttributes: Attributes = DefaultAttributes.filter
 
   override def toString: String = "Filter"
@@ -68,7 +68,7 @@ private[akka] final case class Filter[T](p: T ⇒ Boolean) extends SimpleLinearG
 /**
  * INTERNAL API
  */
-private[akka] final case class TakeWhile[T](p: T ⇒ Boolean) extends SimpleLinearGraphStage[T] {
+final case class TakeWhile[T](p: T ⇒ Boolean) extends SimpleLinearGraphStage[T] {
   override def initialAttributes: Attributes = DefaultAttributes.takeWhile
 
   override def toString: String = "TakeWhile"
@@ -104,7 +104,7 @@ private[akka] final case class TakeWhile[T](p: T ⇒ Boolean) extends SimpleLine
 /**
  * INTERNAL API
  */
-private[stream] final case class DropWhile[T](p: T ⇒ Boolean) extends GraphStage[FlowShape[T, T]] {
+final case class DropWhile[T](p: T ⇒ Boolean) extends GraphStage[FlowShape[T, T]] {
   val in = Inlet[T]("DropWhile.in")
   val out = Outlet[T]("DropWhile.out")
   override val shape = FlowShape(in, out)
@@ -136,7 +136,7 @@ private[stream] final case class DropWhile[T](p: T ⇒ Boolean) extends GraphSta
 /**
  * INTERNAL API
  */
-abstract private[stream] class SupervisedGraphStageLogic(inheritedAttributes: Attributes, shape: Shape) extends GraphStageLogic(shape) {
+abstract class SupervisedGraphStageLogic(inheritedAttributes: Attributes, shape: Shape) extends GraphStageLogic(shape) {
   private lazy val decider = inheritedAttributes.get[SupervisionStrategy].map(_.decider).getOrElse(Supervision.stoppingDecider)
   def withSupervision[T](f: () ⇒ T): Option[T] =
     try { Some(f()) } catch {
@@ -164,7 +164,7 @@ private[stream] object Collect {
 /**
  * INTERNAL API
  */
-private[stream] final case class Collect[In, Out](pf: PartialFunction[In, Out]) extends GraphStage[FlowShape[In, Out]] {
+final case class Collect[In, Out](pf: PartialFunction[In, Out]) extends GraphStage[FlowShape[In, Out]] {
   val in = Inlet[In]("Collect.in")
   val out = Outlet[Out]("Collect.out")
   override val shape = FlowShape(in, out)
@@ -192,7 +192,7 @@ private[stream] final case class Collect[In, Out](pf: PartialFunction[In, Out])
 /**
  * INTERNAL API
  */
-private[akka] final case class Recover[T](pf: PartialFunction[Throwable, T]) extends GraphStage[FlowShape[T, T]] {
+final case class Recover[T](pf: PartialFunction[Throwable, T]) extends GraphStage[FlowShape[T, T]] {
   val in = Inlet[T]("Recover.in")
   val out = Outlet[T]("Recover.out")
   override val shape: FlowShape[T, T] = FlowShape(in, out)
@@ -239,7 +239,7 @@ private[akka] final case class Recover[T](pf: PartialFunction[Throwable, T]) ext
 /**
  * INTERNAL API
  */
-private[akka] final case class Take[T](count: Long) extends SimpleLinearGraphStage[T] {
+final case class Take[T](count: Long) extends SimpleLinearGraphStage[T] {
   override def initialAttributes: Attributes = DefaultAttributes.take
 
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new GraphStageLogic(shape) with InHandler with OutHandler {
@@ -268,7 +268,7 @@ private[akka] final case class Take[T](count: Long) extends SimpleLinearGraphSta
 /**
  * INTERNAL API
  */
-private[akka] final case class Drop[T](count: Long) extends SimpleLinearGraphStage[T] {
+final case class Drop[T](count: Long) extends SimpleLinearGraphStage[T] {
   override def initialAttributes: Attributes = DefaultAttributes.drop
 
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new GraphStageLogic(shape) with InHandler with OutHandler {
@@ -292,7 +292,7 @@ private[akka] final case class Drop[T](count: Long) extends SimpleLinearGraphSta
 /**
  * INTERNAL API
  */
-private[akka] final case class Scan[In, Out](zero: Out, f: (Out, In) ⇒ Out) extends GraphStage[FlowShape[In, Out]] {
+final case class Scan[In, Out](zero: Out, f: (Out, In) ⇒ Out) extends GraphStage[FlowShape[In, Out]] {
   override val shape = FlowShape[In, Out](Inlet("Scan.in"), Outlet("Scan.out"))
 
   override def initialAttributes: Attributes = DefaultAttributes.scan
@@ -338,7 +338,7 @@ private[akka] final case class Scan[In, Out](zero: Out, f: (Out, In) ⇒ Out) ex
 /**
  * INTERNAL API
  */
-private[akka] final case class Fold[In, Out](zero: Out, f: (Out, In) ⇒ Out, decider: Supervision.Decider) extends PushPullStage[In, Out] {
+final case class Fold[In, Out](zero: Out, f: (Out, In) ⇒ Out, decider: Supervision.Decider) extends PushPullStage[In, Out] {
   private[this] var aggregator: Out = zero
 
   override def onPush(elem: In, ctx: Context[Out]): SyncDirective = {
@@ -406,7 +406,7 @@ final case class Intersperse[T](start: Option[T], inject: T, end: Option[T]) ext
 /**
  * INTERNAL API
  */
-private[akka] final case class Grouped[T](n: Int) extends PushPullStage[T, immutable.Seq[T]] {
+final case class Grouped[T](n: Int) extends PushPullStage[T, immutable.Seq[T]] {
   private val buf = {
     val b = Vector.newBuilder[T]
     b.sizeHint(n)
@@ -441,7 +441,7 @@ private[akka] final case class Grouped[T](n: Int) extends PushPullStage[T, immut
 /**
  * INTERNAL API
  */
-private[stream] final case class LimitWeighted[T](n: Long, costFn: T ⇒ Long) extends GraphStage[FlowShape[T, T]] {
+final case class LimitWeighted[T](n: Long, costFn: T ⇒ Long) extends GraphStage[FlowShape[T, T]] {
   val in = Inlet[T]("LimitWeighted.in")
   val out = Outlet[T]("LimitWeighted.out")
   override val shape = FlowShape(in, out)
@@ -473,7 +473,7 @@ private[stream] final case class LimitWeighted[T](n: Long, costFn: T ⇒ Long) e
 /**
  * INTERNAL API
  */
-private[akka] final case class Sliding[T](n: Int, step: Int) extends PushPullStage[T, immutable.Seq[T]] {
+final case class Sliding[T](n: Int, step: Int) extends PushPullStage[T, immutable.Seq[T]] {
   private var buf = Vector.empty[T]
 
   override def onPush(elem: T, ctx: Context[immutable.Seq[T]]): SyncDirective = {
@@ -506,7 +506,7 @@ private[akka] final case class Sliding[T](n: Int, step: Int) extends PushPullSta
 /**
  * INTERNAL API
  */
-private[akka] final case class Buffer[T](size: Int, overflowStrategy: OverflowStrategy) extends DetachedStage[T, T] {
+final case class Buffer[T](size: Int, overflowStrategy: OverflowStrategy) extends DetachedStage[T, T] {
 
   private var buffer: BufferImpl[T] = _
 
@@ -566,7 +566,7 @@ private[akka] final case class Buffer[T](size: Int, overflowStrategy: OverflowSt
 /**
  * INTERNAL API
  */
-private[akka] final case class Batch[In, Out](max: Long, costFn: In ⇒ Long, seed: In ⇒ Out, aggregate: (Out, In) ⇒ Out)
+final case class Batch[In, Out](max: Long, costFn: In ⇒ Long, seed: In ⇒ Out, aggregate: (Out, In) ⇒ Out)
   extends GraphStage[FlowShape[In, Out]] {
 
   val in = Inlet[In]("Batch.in")
@@ -692,7 +692,7 @@ private[akka] final case class Batch[In, Out](max: Long, costFn: In ⇒ Long, se
 /**
  * INTERNAL API
  */
-private[akka] final class Expand[In, Out](extrapolate: In ⇒ Iterator[Out]) extends GraphStage[FlowShape[In, Out]] {
+final class Expand[In, Out](extrapolate: In ⇒ Iterator[Out]) extends GraphStage[FlowShape[In, Out]] {
   private val in = Inlet[In]("expand.in")
   private val out = Outlet[Out]("expand.out")
 
@@ -761,7 +761,7 @@ private[akka] object MapAsync {
 /**
  * INTERNAL API
  */
-private[akka] final case class MapAsync[In, Out](parallelism: Int, f: In ⇒ Future[Out])
+final case class MapAsync[In, Out](parallelism: Int, f: In ⇒ Future[Out])
   extends GraphStage[FlowShape[In, Out]] {
 
   import MapAsync._
@@ -832,7 +832,7 @@ private[akka] final case class MapAsync[In, Out](parallelism: Int, f: In ⇒ Fut
 /**
  * INTERNAL API
  */
-private[akka] final case class MapAsyncUnordered[In, Out](parallelism: Int, f: In ⇒ Future[Out])
+final case class MapAsyncUnordered[In, Out](parallelism: Int, f: In ⇒ Future[Out])
   extends GraphStage[FlowShape[In, Out]] {
 
   private val in = Inlet[In]("MapAsyncUnordered.in")
@@ -904,7 +904,7 @@ private[akka] final case class MapAsyncUnordered[In, Out](parallelism: Int, f: I
 /**
  * INTERNAL API
  */
-private[akka] final case class Log[T](
+final case class Log[T](
   name:       String,
   extract:    T ⇒ Any,
   logAdapter: Option[LoggingAdapter]) extends SimpleLinearGraphStage[T] {
@@ -1021,7 +1021,7 @@ private[stream] object TimerKeys {
   case object GroupedWithinTimerKey
 }
 
-private[stream] final class GroupedWithin[T](n: Int, d: FiniteDuration) extends GraphStage[FlowShape[T, immutable.Seq[T]]] {
+final class GroupedWithin[T](n: Int, d: FiniteDuration) extends GraphStage[FlowShape[T, immutable.Seq[T]]] {
   require(n > 0, "n must be greater than 0")
   require(d > Duration.Zero)
 
@@ -1097,7 +1097,7 @@ private[stream] final class GroupedWithin[T](n: Int, d: FiniteDuration) extends
   }
 }
 
-private[stream] final class Delay[T](d: FiniteDuration, strategy: DelayOverflowStrategy) extends SimpleLinearGraphStage[T] {
+final class Delay[T](d: FiniteDuration, strategy: DelayOverflowStrategy) extends SimpleLinearGraphStage[T] {
   private[this] def timerName = "DelayedTimer"
   override def initialAttributes: Attributes = DefaultAttributes.delay
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new TimerGraphStageLogic(shape) {
@@ -1183,7 +1183,7 @@ private[stream] final class Delay[T](d: FiniteDuration, strategy: DelayOverflowS
   override def toString = "Delay"
 }
 
-private[stream] final class TakeWithin[T](timeout: FiniteDuration) extends SimpleLinearGraphStage[T] {
+final class TakeWithin[T](timeout: FiniteDuration) extends SimpleLinearGraphStage[T] {
 
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new TimerGraphStageLogic(shape) {
     setHandler(in, new InHandler {
@@ -1203,7 +1203,7 @@ private[stream] final class TakeWithin[T](timeout: FiniteDuration) extends Simpl
   override def toString = "TakeWithin"
 }
 
-private[stream] final class DropWithin[T](timeout: FiniteDuration) extends SimpleLinearGraphStage[T] {
+final class DropWithin[T](timeout: FiniteDuration) extends SimpleLinearGraphStage[T] {
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new TimerGraphStageLogic(shape) {
 
     private var allow = false
@@ -1229,7 +1229,7 @@ private[stream] final class DropWithin[T](timeout: FiniteDuration) extends Simpl
 /**
  * INTERNAL API
  */
-private[stream] final class Reduce[T](f: (T, T) ⇒ T) extends SimpleLinearGraphStage[T] {
+final class Reduce[T](f: (T, T) ⇒ T) extends SimpleLinearGraphStage[T] {
   override def initialAttributes: Attributes = DefaultAttributes.reduce
 
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new GraphStageLogic(shape) with InHandler with OutHandler { self ⇒
@@ -1273,7 +1273,7 @@ private[stream] object RecoverWith {
   val InfiniteRetries = -1
 }
 
-private[stream] final class RecoverWith[T, M](maximumRetries: Int, pf: PartialFunction[Throwable, Graph[SourceShape[T], M]]) extends SimpleLinearGraphStage[T] {
+final class RecoverWith[T, M](maximumRetries: Int, pf: PartialFunction[Throwable, Graph[SourceShape[T], M]]) extends SimpleLinearGraphStage[T] {
   require(maximumRetries >= -1, "number of retries must be non-negative or equal to -1")
   override def initialAttributes = DefaultAttributes.recoverWith
 
@@ -1331,7 +1331,7 @@ private[stream] final class RecoverWith[T, M](maximumRetries: Int, pf: PartialFu
 /**
  * INTERNAL API
  */
-private[stream] final class StatefulMapConcat[In, Out](f: () ⇒ In ⇒ immutable.Iterable[Out]) extends GraphStage[FlowShape[In, Out]] {
+final class StatefulMapConcat[In, Out](val f: () ⇒ In ⇒ immutable.Iterable[Out]) extends GraphStage[FlowShape[In, Out]] {
   val in = Inlet[In]("StatefulMapConcat.in")
   val out = Outlet[Out]("StatefulMapConcat.out")
   override val shape = FlowShape(in, out)
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/TLSActor.scala b/akka-stream/src/main/scala/akka/stream/impl/io/TLSActor.scala
index 9ae2505744..9a2a4c3cd9 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/TLSActor.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/TLSActor.scala
@@ -23,7 +23,7 @@ import akka.stream.TLSProtocol._
 /**
  * INTERNAL API.
  */
-private[akka] object TLSActor {
+object TLSActor {
 
   def props(
     settings:     ActorMaterializerSettings,
@@ -46,7 +46,7 @@ private[akka] object TLSActor {
 /**
  * INTERNAL API.
  */
-private[akka] class TLSActor(
+class TLSActor(
   settings:          ActorMaterializerSettings,
   sslContext:        SSLContext,
   externalSslConfig: Option[AkkaSSLConfig],
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala b/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
index b93b385597..01a3692c87 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
@@ -295,7 +295,7 @@ private[stream] object TcpConnectionStage {
 /**
  * INTERNAL API
  */
-private[stream] class IncomingConnectionStage(connection: ActorRef, remoteAddress: InetSocketAddress, halfClose: Boolean)
+class IncomingConnectionStage(connection: ActorRef, remoteAddress: InetSocketAddress, halfClose: Boolean)
   extends GraphStage[FlowShape[ByteString, ByteString]] {
   import TcpConnectionStage._
 
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/TlsModule.scala b/akka-stream/src/main/scala/akka/stream/impl/io/TlsModule.scala
index e5b31bd6bf..4abaa2e9de 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/TlsModule.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/TlsModule.scala
@@ -11,13 +11,13 @@ import com.typesafe.sslconfig.akka.AkkaSSLConfig
 /**
  * INTERNAL API.
  */
-private[akka] final case class TlsModule(plainIn: Inlet[SslTlsOutbound], plainOut: Outlet[SslTlsInbound],
-                                         cipherIn: Inlet[ByteString], cipherOut: Outlet[ByteString],
-                                         shape: Shape, attributes: Attributes,
-                                         sslContext:   SSLContext,
-                                         sslConfig:    Option[AkkaSSLConfig],
-                                         firstSession: NegotiateNewSession,
-                                         role:         TLSRole, closing: TLSClosing, hostInfo: Option[(String, Int)]) extends AtomicModule {
+final case class TlsModule(plainIn: Inlet[SslTlsOutbound], plainOut: Outlet[SslTlsInbound],
+                           cipherIn: Inlet[ByteString], cipherOut: Outlet[ByteString],
+                           shape: Shape, attributes: Attributes,
+                           sslContext:   SSLContext,
+                           sslConfig:    Option[AkkaSSLConfig],
+                           firstSession: NegotiateNewSession,
+                           role:         TLSRole, closing: TLSClosing, hostInfo: Option[(String, Int)]) extends AtomicModule {
 
   override def withAttributes(att: Attributes): TlsModule = copy(attributes = att)
   override def carbonCopy: TlsModule =
@@ -35,7 +35,7 @@ private[akka] final case class TlsModule(plainIn: Inlet[SslTlsOutbound], plainOu
 /**
  * INTERNAL API.
  */
-private[akka] object TlsModule {
+object TlsModule {
   def apply(attributes: Attributes, sslContext: SSLContext, sslConfig: Option[AkkaSSLConfig], firstSession: NegotiateNewSession, role: TLSRole, closing: TLSClosing, hostInfo: Option[(String, Int)]): TlsModule = {
     val name = attributes.nameOrDefault(s"StreamTls($role)")
     val cipherIn = Inlet[ByteString](s"$name.cipherIn")
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
index 88ba60b061..b49042c447 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
@@ -96,7 +96,7 @@ object BidiFlow {
 }
 
 final class BidiFlow[-I1, +O1, -I2, +O2, +Mat](delegate: scaladsl.BidiFlow[I1, O1, I2, O2, Mat]) extends Graph[BidiShape[I1, O1, I2, O2], Mat] {
-  private[stream] override def module = delegate.module
+  override def module = delegate.module
   override def shape = delegate.shape
 
   def asScala: scaladsl.BidiFlow[I1, O1, I2, O2, Mat] = delegate
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
index 5ec142d2bb..70e500dadc 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
@@ -73,7 +73,7 @@ final class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends
   import scala.collection.JavaConverters._
 
   override def shape: FlowShape[In, Out] = delegate.shape
-  private[stream] def module: StreamLayout.Module = delegate.module
+  def module: StreamLayout.Module = delegate.module
 
   override def toString: String = delegate.toString
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
index 0aa1df808d..97ea1214aa 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
@@ -272,7 +272,7 @@ object Sink {
 final class Sink[-In, +Mat](delegate: scaladsl.Sink[In, Mat]) extends Graph[SinkShape[In], Mat] {
 
   override def shape: SinkShape[In] = delegate.shape
-  private[stream] def module: StreamLayout.Module = delegate.module
+  def module: StreamLayout.Module = delegate.module
 
   override def toString: String = delegate.toString
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
index 2362794819..94b31c0fd3 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -414,7 +414,7 @@ final class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Grap
 
   override def shape: SourceShape[Out] = delegate.shape
 
-  private[stream] def module: StreamLayout.Module = delegate.module
+  def module: StreamLayout.Module = delegate.module
 
   override def toString: String = delegate.toString
 
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
index 3bc954ebd4..b27d817df7 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
@@ -10,7 +10,7 @@ import akka.stream.impl.Timers
 
 import scala.concurrent.duration.FiniteDuration
 
-final class BidiFlow[-I1, +O1, -I2, +O2, +Mat](private[stream] override val module: Module) extends Graph[BidiShape[I1, O1, I2, O2], Mat] {
+final class BidiFlow[-I1, +O1, -I2, +O2, +Mat](override val module: Module) extends Graph[BidiShape[I1, O1, I2, O2], Mat] {
   override def shape = module.shape.asInstanceOf[BidiShape[I1, O1, I2, O2]]
 
   def asJava: javadsl.BidiFlow[I1, O1, I2, O2, Mat] = new javadsl.BidiFlow(this)
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
index a2636d4bcb..5e0aad72f8 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
@@ -25,7 +25,7 @@ import akka.NotUsed
 /**
  * A `Flow` is a set of stream processing steps that has one open input and one open output.
  */
-final class Flow[-In, +Out, +Mat](private[stream] override val module: Module)
+final class Flow[-In, +Out, +Mat](override val module: Module)
   extends FlowOpsMat[Out, Mat] with Graph[FlowShape[In, Out], Mat] {
 
   override val shape: FlowShape[In, Out] = module.shape.asInstanceOf[FlowShape[In, Out]]
@@ -335,7 +335,7 @@ object RunnableGraph {
 /**
  * Flow with attached input and output, can be executed.
  */
-final case class RunnableGraph[+Mat](private[stream] val module: StreamLayout.Module) extends Graph[ClosedShape, Mat] {
+final case class RunnableGraph[+Mat](val module: StreamLayout.Module) extends Graph[ClosedShape, Mat] {
   require(module.isRunnable)
   override def shape = ClosedShape
 
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
index a77e18f13d..e2964f727e 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
@@ -26,7 +26,7 @@ import scala.util.{ Failure, Success, Try }
  * A `Sink` is a set of stream processing steps that has one open input and an attached output.
  * Can be used as a `Subscriber`
  */
-final class Sink[-In, +Mat](private[stream] override val module: Module)
+final class Sink[-In, +Mat](override val module: Module)
   extends Graph[SinkShape[In], Mat] {
 
   override val shape: SinkShape[In] = module.shape.asInstanceOf[SinkShape[In]]
@@ -89,7 +89,7 @@ final class Sink[-In, +Mat](private[stream] override val module: Module)
 object Sink {
 
   /** INTERNAL API */
-  private[stream] def shape[T](name: String): SinkShape[T] = SinkShape(Inlet(name + ".in"))
+  def shape[T](name: String): SinkShape[T] = SinkShape(Inlet(name + ".in"))
 
   /**
    * A graph with the shape of a sink logically is a sink, this method makes
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index 62cba7bba1..3ce9ddc387 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -27,7 +27,7 @@ import scala.compat.java8.FutureConverters._
  * an “atomic” source, e.g. from a collection or a file. Materialization turns a Source into
  * a Reactive Streams `Publisher` (at least conceptually).
  */
-final class Source[+Out, +Mat](private[stream] override val module: Module)
+final class Source[+Out, +Mat](override val module: Module)
   extends FlowOpsMat[Out, Mat] with Graph[SourceShape[Out], Mat] {
 
   override type Repr[+O] = Source[O, Mat @uncheckedVariance]
@@ -170,7 +170,7 @@ final class Source[+Out, +Mat](private[stream] override val module: Module)
 
 object Source {
   /** INTERNAL API */
-  private[stream] def shape[T](name: String): SourceShape[T] = SourceShape(Outlet(name + ".out"))
+  def shape[T](name: String): SourceShape[T] = SourceShape(Outlet(name + ".out"))
 
   /**
    * Helper to create [[Source]] from `Publisher`.
diff --git a/akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala b/akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala
index cab6d14a26..493335fa9c 100644
--- a/akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala
+++ b/akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala
@@ -23,11 +23,11 @@ abstract class GraphStageWithMaterializedValue[+S <: Shape, +M] extends Graph[S,
 
   protected def initialAttributes: Attributes = Attributes.none
 
-  final override private[stream] lazy val module: Module = GraphStageModule(shape, initialAttributes, this)
+  final override lazy val module: Module = GraphStageModule(shape, initialAttributes, this)
 
   final override def withAttributes(attr: Attributes): Graph[S, M] = new Graph[S, M] {
     override def shape = GraphStageWithMaterializedValue.this.shape
-    override private[stream] def module = GraphStageWithMaterializedValue.this.module.withAttributes(attr)
+    override def module = GraphStageWithMaterializedValue.this.module.withAttributes(attr)
 
     override def withAttributes(attr: Attributes) = GraphStageWithMaterializedValue.this.withAttributes(attr)
   }
diff --git a/akka-stream/src/main/scala/akka/stream/stage/Stage.scala b/akka-stream/src/main/scala/akka/stream/stage/Stage.scala
index 1ddb08d392..aa44f6859d 100644
--- a/akka-stream/src/main/scala/akka/stream/stage/Stage.scala
+++ b/akka-stream/src/main/scala/akka/stream/stage/Stage.scala
@@ -34,7 +34,7 @@ sealed trait Stage[-In, +Out]
 /**
  * INTERNAL API
  */
-private[stream] object AbstractStage {
+object AbstractStage {
 
   private class PushPullGraphLogic[In, Out](
     private val shape: FlowShape[In, Out],
diff --git a/project/MiMa.scala b/project/MiMa.scala
index 53e0ff285f..43bd291a6f 100644
--- a/project/MiMa.scala
+++ b/project/MiMa.scala
@@ -900,7 +900,10 @@ object MiMa extends AutoPlugin {
         
         // #20846 change of internal Status message
         ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.cluster.pubsub.protobuf.msg.DistributedPubSubMessages#StatusOrBuilder.getReplyToStatus"),
-        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.cluster.pubsub.protobuf.msg.DistributedPubSubMessages#StatusOrBuilder.hasReplyToStatus")
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.cluster.pubsub.protobuf.msg.DistributedPubSubMessages#StatusOrBuilder.hasReplyToStatus"),
+
+        // #20543 GraphStage subtypes should not be private to akka
+        ProblemFilters.exclude[DirectAbstractMethodProblem]("akka.stream.ActorMaterializer.actorOf")
       )
     )
   }