We’re building a custom chat UI in Kotlin for Android and decided to ditch the Messenger widget entirely. Instead, we’re connecting directly to the WebSocket endpoint for web messaging sessions. The connection handshake works fine, and we’re getting the session_id back in the JSON payload.
The problem is sending the actual text. I’m trying to post a message to the session but getting a 403 Forbidden. Is there a specific header I’m missing for the guest token?