Reply to a message
POST/api/sessions/:sessionId/messages/reply
Reply to a message
Request
Responses
- 201
- 400
- 404
- 409
Reply sent
The request was rejected before anything was sent. Among the causes: the recipient could not be addressed — WhatsApp reports no deliverable id for that chatId, which is how it says the number is not on WhatsApp — as well as body validation and a session that is not active.
No such message — the id is outside the engine's lookup window (roughly the last hundred messages of the chat, or absent from the Baileys store) or the message was revoked.
The session is not connected — an engine exists for it but is not ready: disconnected, reconnecting, or still initializing, so the request never reached WhatsApp. Wait for ready and retry. A session that was never started answers 400 instead, and the session lifecycle routes answer 409 for a conflicting state rather than this. One window answers this while the session still reads ready: WhatsApp Web periodically reloads its own page and the engine re-injects into it — for those few seconds the answer is a 409 naming the reload; retry shortly.