Per-plan API rate and concurrency limits are now published

July 19, 2026 1 min read

The API limits reference now lists per-plan rate limits (requests per second, plus an Agents burst) and concurrency limits for both the TTS and Agents surfaces, and 429 responses carry a docs_url plus distinct rate_limited and concurrency_limited error codes.

Luke Oliff Developer Relations · SpeechifyAI Labs

The API limits reference now spells out the per-plan rate limits (sustained requests per second, plus a burst allowance on Agents) and concurrency limits (simultaneous in-flight requests) for both the audio (TTS) and Agents surfaces. Limits apply per account, not per API key.

429 Too Many Requests responses are now self-describing: a Retry-After header, an error.code that distinguishes rate_limited from concurrency_limited, and an error.docs_url that links straight to the limits reference and how to raise them.

See the Build changelog for the summary.