API: Concurrency Limits for TTS Endpoints
We’ve introduced concurrency limits to prevent abuse and ensure fair usage across all users. These limits restrict the number of simultaneous in-flight text-to-speech requests per user.
Concurrency Limits
What This Means
- Free users are limited to 1 concurrent in-flight TTS request at a time
- Paid users can have up to 15 concurrent in-flight TTS requests
- Concurrency limits are enforced per user account, not per API key
- When the limit is exceeded, you’ll receive a
429 Too Many Requestsresponse with aRetry-Afterheader
Affected Endpoints
POST /v1/audio/speechPOST /v1/audio/stream
Concurrency limits work alongside rate limits. Both must be satisfied for a request to proceed. If you exceed the concurrency limit, wait for your current request(s) to complete before sending new ones.