Request Limits

VUI Labs applies sliding-window request limits to the synchronous and streaming TTS endpoints.

Endpoint	Project-space limit	Platform-wide limit	Additional limit
POST /v1/text-to-speech	600 requests per 60 seconds	10 requests per second	—
POST /v1/text-to-speech/stream	600 requests per 60 seconds	10 requests per second	2 requests per second per authenticated user

The project-space limit is shared by API keys in the same project space. The platform-wide limit is shared by all callers. Current project limits are shown in Developer → Project Spaces → select a project → Request Limits.

When one of these gateway limits is reached, the API returns HTTP 429 with the standard JSON error body and error_code: 10014. If you frequently reach a limit, you can request a capacity increase.

To request a capacity increase, email contact@vuilabs.ai with the project ID, expected request rate, concurrency, and traffic pattern.