Guides

Rate Limits

SAUTI API rate limits, response headers, and guidance on handling 429 errors.

Per-minute sliding windows

Rate limits are applied per API key using sliding windows. Each endpoint category has its own limit.

Endpoint category	Requests / minute	Examples
Synthesis	10	`POST /v1/text-to-speech/*`, `POST /v1/tts/jobs`
Status / polling	60	`GET /v1/tts/jobs/*`
Default	30	`GET /v1/voices`, all other endpoints

Rate limit headers

Every response includes headers indicating your current quota state.

Header	Description
`X-RateLimit-Limit`	Maximum requests allowed in the current window
`X-RateLimit-Remaining`	Requests remaining before you are limited
`X-RateLimit-Reset`	Unix timestamp at which the current window resets.
`Retry-After`	Seconds to wait before retrying. Present only on `429` responses.

Handling 429 errors

When you exceed your limit, the API returns HTTP 429 with a Retry-After header. Do not retry immediately — wait the specified number of seconds, then use exponential backoff for subsequent failures.

python

import time
import requests

def request_with_backoff(url, headers, payload, max_retries=3):
    for attempt in range(max_retries):
        response = requests.post(url, headers=headers, json=payload)
        if response.status_code != 429:
            return response
        retry_after = int(response.headers.get("Retry-After", 10))
        print(f"Rate limited. Retrying in {retry_after}s...")
        time.sleep(retry_after)
    raise Exception("Max retries exceeded")

json

{
  "type": "https://sauti.finiflowlabs.com/errors/rate_limit_exceeded",
  "title": "Rate Limit Exceeded",
  "status": 429,
  "detail": "You have exceeded 10 requests per minute for synthesis. Try again shortly."
}

Requesting higher limits

For production workloads that require higher rate limits, email hello@finiflowlabs.com with:

Your use case and deployment environment
Expected peak request volume per minute
Endpoints you are using

We are in early access. Limits are intentionally conservative while we scale infrastructure.