Webchat API 503s at 50 concurrent sessions

General Discussion
1

I’m completely stumped as to why the /api/v2/webchat/sessions endpoint returns HTTP 503 Service Unavailable when concurrent JMeter threads hit 50. Running from Singapore with basic auth tokens. The load is steady, not spiky.

Config is simple POST requests with minimal payload. No custom data attached. Just trying to establish connections.

Any ideas on the default connection limit for free tier accounts? Logs show gateway timeout on the platform side.

2

The problem here is hitting the default WebSocket concurrency limit for the free tier. It caps at 25 simultaneous sessions, causing the 503 when JMeter exceeds that threshold. Check the documentation on tier-specific limits: https://help.genesys.cloud/article/12345. You need to upgrade or reduce concurrent threads.

3

This seems like a classic case of hitting platform guardrails without realizing the underlying architecture constraints. The previous suggestion about the free tier limit is technically correct, but there is a more subtle issue with the authentication method being used. Basic Auth tokens are not designed for high-concurrency stateful connections like Webchat sessions. They often trigger additional validation overhead that exacerbates latency and leads to 503s well before the hard session limit is reached.

  • Switch to OAuth2 Bearer tokens. These are cached and validated more efficiently by the gateway, reducing handshake time significantly under load.
  • Verify the client_id permissions in the AppFoundry portal. Ensure the application has webchat:session:write scope explicitly granted, not just inherited.
  • Implement exponential backoff in your JMeter script. The platform API rate limits are enforced per organization, and rapid retries can trigger temporary bans on the IP range.
  • Check the X-Request-Id headers in the 503 responses. This helps correlate the failure with specific gateway nodes, which is useful if you need to escalate to support with concrete evidence of a regional outage.