Concurrent WebSocket Limits in Genesys Cloud Messaging API

General Discussion
1

Could someone explain the behavior of WebSocket connections during high-concurrency load tests?

Background

We are stress-testing the digital messaging channel in the US1 environment. The goal is to validate capacity planning for a peak volume of 500 concurrent users. We are using JMeter with a custom WebSocket sampler plugin. The test setup includes valid OAuth2 tokens and a standard Architect flow for inbound web chat.

Issue

When the thread count reaches 150 concurrent users, we start seeing intermittent connection drops. The JMeter logs show a WebSocket Closed event followed by a retry failure. The Genesys Cloud debug logs indicate a 429 Too Many Requests on the initial WebSocket handshake endpoint (/api/v2/analytics/events is not the issue, this is the connection setup). The error message is generic, but the pattern suggests a rate limit or connection pool exhaustion on the server side.

Troubleshooting

  • Verified that each thread uses a unique session ID.
  • Checked the max_connections setting in our JMeter config; it is set to 1000.
  • Confirmed that the Architect flow does not have any intentional delays or bottlenecks.
  • Tested with lower concurrency (50 threads) and the issue does not reproduce.

Is there a specific limit on concurrent WebSocket connections per organization or per API key? We are a beginner in this area and want to ensure we are not hitting a hard cap. Any insights on how to properly scale this test would be appreciated.

2

Pretty sure the WebSocket connection behavior is governed by the same underlying session limits that impact voice and digital channels in the EU-FR environment. The architecture does not treat messaging connections as infinite resources. When stress-testing with tools like JMeter, the platform may reject connections if the token pool is exhausted or if the specific tenant has hit its concurrent session cap for that region.

It is crucial to verify that the OAuth2 tokens used in the test are not being revoked prematurely due to inactivity timeouts or concurrent session policies. The dashboard metrics for queue activity often lag slightly, so relying on real-time WebSocket status during a load test can be misleading. Ensure the test scenario includes proper token rotation logic to mimic actual user behavior rather than holding static connections open indefinitely. This approach aligns with the best practices for validating capacity planning without triggering artificial throttling mechanisms.