API rate limits
Upload, concurrency, and timeout limits for ASR and TTS requests.
Speech-to-Text (ASR)
| Limit | Value |
|---|
| Max file size | 500 MB |
| Max audio duration per file | 4 hours |
| Concurrent requests (default tier) | 16 |
| HTTP request timeout | Use at least 120 s for long audio |
| WebSocket inactivity timeout | 300 s (configurable up to 3600 s) |
Text-to-Speech (TTS)
| Limit | Value |
|---|
| Max text length per request | 10,000 characters |
| Recommended per-request | Under 500 characters for best quality; split longer text |
| HTTP request timeout | Set to at least 120 s for long text |
| Concurrent requests (default tier) | 16 |
