Add or remove a reaction to a message
POST/api/sessions/:sessionId/messages/react
Add or remove a reaction to a message
Request
Responses
- 200
- 400
- 404
- 409
Reaction added or removed. Send empty emoji to remove reaction.
Session not active or message not found
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engine's lookup window (roughly the last hundred messages of the chat, or absent from the Baileys store) or the message was revoked.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.