Get QR code for session authentication

GET 
/api/sessions/:sessionId/qr

Get QR code for session authentication

Request

Responses

200

QR code data

400

QR code not ready or session already authenticated

404

Session not found

409

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.