Join a group via invite code
POST/api/sessions/:sessionId/groups/join
Join a group via invite code
Request
Responses
- 200
- 400
- 401
- 403
- 409
- 503
Joined the group
Invalid or expired invite code, or session is not started
The API key is missing, unknown, revoked, or expired
The API key's role, session or chat scope, or IP allow-list does not allow this operation
The session is not connected: an engine exists for it but is not ready, meaning 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, and for those few seconds the answer is a 409 naming the reload; retry shortly.
WhatsApp did not answer within the request budget. The change may or may not have been applied — the gateway stopped waiting for a confirmation that never came. On Baileys, also answered when WhatsApp rate-limits or times out the request (code 429 or 408); retry after a pause.