Thanks Stuart. I need to avoid annotations since this will be configured dynamically. I was wrong about the version, right now i'm on 2.0.9.Final. I'm trying to create a websocket proxy. I was able to get the ReceiveListener registered in Undertow and create a WebSocketClient. I'm trying to pipe the data from the client through Undertow to the server, starting with a Text message: @Override protected void onText(WebSocketChannel webSocketChannel, StreamSourceFrameChannel messageChannel) throws IOException { PooledByteBuffer b = pool.allocate(); ByteBuffer buffer = b.getBuffer(); while (messageChannel.read(buffer) > 0) { WebSockets.sendText(buffer, wsClient, null); } b.close(); } The message sent to the downstream websocket server isn't right though (and the server rejects it). The frame from wireshark just shows a buffer of "\000\000...". I think I'm close but I don't see an example of how to do this. Any suggestions or pointers would be greatly appreciated. Thanks Marc Boorshtein On Thu, Nov 29, 2018 at 5:07 PM Stuart Douglas <sdouglas(a)redhat.com&gt; wrote: