Agent Scripting API 429 errors during high-concurrency JMeter load test

General Discussion
1

I can’t seem to figure out why the Genesys Cloud Agent Scripting API is returning 429 Too Many Requests when we simulate a moderate load of concurrent agent sessions. We are running a performance validation test from our Singapore staging environment to establish baseline capacity for a new deployment. The goal is to ensure that script updates and fetches remain stable when 500 agents are simultaneously active and interacting with custom scripting elements.

The test setup uses JMeter 5.6.2 with a thread group configured for 500 users. Each thread simulates an agent session by first authenticating via the OAuth2 endpoint, then immediately polling the /api/v2/scripts endpoint to retrieve the latest script version associated with their interaction. The polling interval is set to 2 seconds. After just 60 seconds into the test, the success rate drops from 98% to roughly 40%. The failure logs are filled with 429 responses, even though the API documentation suggests the rate limit for this endpoint should handle significantly higher throughput per tenant.

We have verified that the authentication tokens are valid and not expiring prematurely. The issue seems specific to the frequency of the script retrieval requests rather than the initial login overhead. We are trying to determine if this is a hard limit on the staging environment or if our request pattern is triggering a protective mechanism we are not aware of. The error response does not provide a Retry-After header, which makes it difficult to implement an effective backoff strategy in the JMeter script.

Here is what we have attempted so far:

  • Reduced the concurrent thread count to 200 and extended the polling interval to 5 seconds, which eliminated the 429 errors but does not reflect our expected production load pattern.
  • Added a custom header X-Genesys-Client-ID to the requests to see if client identification helps with rate limit bucketing, but the behavior remained identical.

Can anyone share insights on the specific rate limiting thresholds for the Agent Scripting API under load? We need to know if we should adjust our polling strategy or if there is a configuration on the platform side that needs adjustment for high-concurrency scenarios.

2

The official documentation states that the 429 responses are triggered by exceeding the specific rate limits for the scripting endpoints, which are distinct from general API quotas. When simulating high concurrency with JMeter, the default request pacing often overwhelms the Genesys Cloud gateway before the application logic even processes the payload.

  1. Implement exponential backoff in your JMeter script. Instead of immediate retries on 429, add a randomized delay between attempts to smooth out the request burst.
  2. Verify the X-Genesys-Client-Version header is present. Missing client version headers can cause stricter rate limiting enforcement on legacy endpoints.
  3. Check the Retry-After header in the 429 response body. Your script should parse this integer value and wait exactly that many seconds before resuming requests.

In our ServiceNow integrations, we see similar throttling when webhook payloads are malformed, but here the issue is purely volumetric. Ensure your JMeter thread group uses a “Throughput Shaping Timer” to cap the requests per second, aligning with the documented limits for the api/v2/scripts resource. This usually stabilizes the load test immediately.