Could someone explain why our Genesys Cloud Edge BYOC setup is rejecting WebSocket connections during load testing? We are running JMeter 5.4.1 from our Singapore office to simulate agent login traffic. The test plan uses HTTP Request samplers to fetch the authorization_code and then attempts to open the WebSocket connection to the Edge endpoint.
With a low thread count of 10, everything works fine. But as soon as we ramp up to 50 concurrent threads, about 60% of the connections fail immediately. The browser console in our dev environment shows a clean handshake, but the headless JMeter script hits a wall.
WebSocket connection to ‘wss://edge-eu-west-1.amazonaws.com/…’ failed: Error during WebSocket handshake: Unexpected response code: 403
The 403 Forbidden response suggests an authentication issue, but we are reusing the same valid JWT token for all threads in the test. The token is generated once before the ramp-up starts. I suspect there might be a rate limit on the token validation endpoint or a concurrency limit on the WebSocket handshake itself that isn’t documented. We are using the genesys-cloud-webchat-sdk version 2.0.0 for reference in our manual tests.
Is there a known limit on concurrent WebSocket handshakes per tenant or IP range? Or does the JWT need to be refreshed more frequently under load? We are trying to determine if this is a configuration error on our side or a platform constraint.
If I remember correctly… the issue likely stems from how the WebSocket upgrade handshake is handled under load, specifically regarding the authentication token’s validity window. In Zendesk, API tokens often had broader scope or longer lifespans, but Genesys Cloud’s BYOC Edge requires a fresh, valid JWT for each WebSocket connection attempt. When JMeter ramps to 50 threads, the initial authorization_code exchange might be timing out or returning a token that expires before the subsequent WebSocket upgrade request completes.
Try splitting the test plan into two distinct phases. First, use an HTTP Request sampler to obtain the access_token and store it in a JMeter variable. Then, use a separate WebSocket Open sampler that references this variable. Ensure the WebSocket sampler includes the Authorization: Bearer ${access_token} header explicitly. Also, check if your Edge configuration has rate limiting on the WebSocket endpoint itself. Genesys Cloud’s Edge infrastructure is stricter about concurrent connections than Zendesk’s older ticketing API endpoints were. You might need to add a small delay (500ms) between the token fetch and the WebSocket open to ensure the token is fully propagated. Additionally, verify that the Edge endpoint URL in your JMeter script matches the exact region-specific endpoint (e.g., euc1 for Paris, not us-east-1). Misconfigured region endpoints often return 403s that look like auth failures. This approach usually stabilizes the handshake under load.
this looks like a token reuse issue. gc edges are strict on jwt expiry. add a correlation variable in jmeter to fetch a fresh auth token per thread instead of sharing one.
Make sure you configure your JMeter test plan to treat each virtual agent as an independent session with its own authentication lifecycle. The 403 errors during ramp-up usually indicate that the initial authorization code is being reused across multiple threads or that the JWT expiration window is too narrow for the handshake duration. In my experience with large-scale schedule publishing, concurrent requests often collide when they share state, and WebSocket handshakes are no different. You need to ensure that every thread generates a unique token immediately before the connection attempt, rather than relying on a single token fetched at the start of the test.
Set up a HTTP Request sampler dedicated to token generation within the thread group. Use a regular expression extractor to capture the access_token from the JSON response. Then, reference this variable in the WebSocket upgrade headers. Here is a snippet of how the header manager should look:
This approach mirrors how we handle agent self-service API calls during peak shift swaps. If you are simulating 50 agents, you need 50 distinct tokens. Additionally, check your Edge configuration for any rate-limiting policies on the WebSocket endpoint. Sometimes the infrastructure allows the connection but rejects the payload if the headers are malformed or stale. Verifying the token validity period in the Genesys Cloud admin console can also help; extending the expiration slightly might provide enough buffer for the JMeter ramp-up phase without compromising security.
It depends, but generally… the Edge ingress layer validates token freshness strictly under load. The 403s indicate shared state expiration. Ensure each JMeter thread fetches a unique JWT. The bulk export manifest shows similar failures when metadata isn’t isolated per session. Check Genesys Cloud BYOC Auth Docs for the required per-request token scope.