Can anyone explain why the screen recording upload endpoint is failing with 400 bad request when we push more than 50 concurrent sessions in our jmeter test plan? we are using the latest version of the genesys cloud sdk for java (version 1.10.2) and trying to validate the throughput limits for the recording ingestion service. the test plan is configured to simulate agents starting screen recordings simultaneously, which triggers the upload process via the /api/v2/recordings/screen endpoint. when the concurrency is low, say 10 threads, everything works fine and the recordings are stored correctly. but once we increase the thread group to 50 or more, we start seeing a high percentage of 400 errors. the error message in the response body is quite vague, just saying “invalid request payload”. we have checked the jmeter debug sampler and the json payload structure looks identical to the successful requests. we are also respecting the retry-after header from any 429 responses we get earlier in the chain, so it is not a rate limiting issue at the api gateway level. our environment is a large scale deployment with high agent density, so we need to understand the true capacity of the screen recording feature. we have tried adding a constant timer between the recording start and the upload request, but it did not help. the websocket connection for the recording session seems stable, but the final upload step fails. we are using the standard oauth2 client credentials flow for authentication. is there a specific limit on the number of parallel screen recording uploads per tenant or per ip address that is not documented? we need to adjust our load test configuration to match the actual platform capabilities. any insights into the backend processing limits for screen recordings would be appreciated. we are currently blocked on our capacity planning report for the next quarter. the logs show no specific validation errors, just the generic 400 status. we have also checked the recording config settings in the admin portal and everything seems to be set to default. please let me know if you need more details from the jmeter xml file or the specific http request headers.
This is actually a known issue…
Can anyone clarify why the screen recording upload endpoint is failing with 400 bad request when we push more than 50 concurrent sessions in our jmeter test plan?
The root cause here is almost certainly not the ingestion service itself, but rather how the Genesys Cloud API handles concurrent state mutations for recording metadata. When you simulate 50+ agents starting recordings simultaneously, you are likely triggering race conditions on the underlying resource locks or hitting implicit throttling on the metadata creation service, which returns a 400 when the payload context is invalid due to timing conflicts.
From an AppFoundry partner perspective, we see this frequently when clients attempt to validate throughput without accounting for the asynchronous nature of Genesys Cloud’s event-driven architecture. The /api/v2/recordings/screen endpoint expects specific headers and a consistent session state. Under heavy load, the SDK may retry before the previous state is fully committed, leading to malformed requests.
To mitigate this, you should implement exponential backoff in your JMeter test plan for any 400 or 429 responses. Additionally, ensure your Java SDK client is configured with proper connection pooling and timeout settings. Here is a recommended configuration snippet for the Java SDK to handle concurrency more gracefully:
ApiClient client = ApiClient.getDefaultApiClient();
client.setMaxConnections(100); // Increase max connections
client.setReadTimeout(30000); // Increase read timeout
client.setConnectTimeout(10000);
Furthermore, verify that your test data includes unique recordingId parameters for each concurrent session. Reusing IDs or failing to generate them atomically during load tests will cause the server to reject the payload as invalid. The 400 error is often a mask for a deeper state inconsistency rather than a simple rate limit. Adjusting the ramp-up period in JMeter to allow Genesys Cloud to process metadata sequentially can also provide more accurate throughput data without triggering these errors.
It depends, but generally… the discrepancy stems from conflating client-side upload initiation with server-side ingestion limits. The 400 Bad Request is rarely a throughput cap on the /api/v2/recordings/screen endpoint itself; rather, it indicates a malformed payload or a missing required header in the concurrent stream. When simulating 50+ agents, the Java SDK often fails to serialize the Content-Disposition header correctly under high thread contention, leading to a malformed multipart/form-data boundary.
The Genesys Cloud documentation explicitly states that each screen recording upload must include a unique x-genesys-recording-id header. If your JMeter script reuses static UUIDs or fails to generate them per-thread, the API rejects the request before it even hits the storage layer. Furthermore, ensure the Authorization Bearer token is refreshed per session. A single long-lived token across 50 threads will hit rate limits on the OAuth service, causing the subsequent recording upload requests to inherit an invalid or expired token context, resulting in a 400 error instead of the expected 401.
To verify, inspect the raw HTTP response body for the error_code. If it is INVALID_REQUEST, the issue is payload structure. If it is AUTHENTICATION_FAILED, the token is stale. Adjust the JMeter HTTP Header Manager to include dynamic variables for the recording ID and ensure the Content-Type matches multipart/form-data exactly, including the boundary string generated by the SDK.
Warning: Do not assume the 400 is a rate limit. Genesys Cloud uses 429 Too Many Requests for throttling. A 400 is strictly a client-side error. Forcing retries without fixing the payload structure will exacerbate the issue and potentially trigger account-level abuse detection mechanisms.
TL;DR: Check payload serialization.
This is caused by the Java SDK failing to serialize the Content-Disposition header correctly under high thread contention. The server rejects the malformed request, not because of a throughput limit.