Guest API messaging without widget

Trying to build a custom chat client using the Guest API. Skipping the Messenger widget entirely.

Got the guest ID by creating a guest session. Then posting a message with the right payload.

{ “text”: “hello”, “type”: “text” }

Returns 200 OK. But the platform never receives it. No webhook fires. Is there a specific header or flow step missing to actually queue this for routing? Just getting the guest ID doesn’t seem to activate the channel.

You’re missing the externalContactId in the message payload body. The API needs that ID to link the message to the guest you just created.

{
 "externalContactId": "your-guest-id-here",
 "text": "hello",
 "type": "text"
}