Send a document/file
POST/api/sessions/:sessionId/messages/send-document
Send a document/file
Request
Responses
- 201
- 400
- 409
- 501
Document sent
Session not active or invalid request
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.
Sending media to a channel (<id>@newsletter) is not supported by the whatsapp-web.js engine — the page method it needs was removed by a WhatsApp Web update. Text to a channel still works.