---
title: API Rate Limiting
slug: api/api-rate-limiting
createdAt: 2026-11-12T02:26:15.405Z
---

The Sine API enforces request rate limits and returns rate-limit information in response headers. Requests exceeding an applicable limit receive `HTTP 429: Too Many Requests`. Your application should use these headers to pace requests and determine when to retry.

## Headers

| **Header**              | **Description**                                                         | **Example**                                                          |
| ----------------------- | ----------------------------------------------------------------------- | -------------------------------------------------------------------- |
| `x-ratelimit-limit`     | The current request quota, followed by the applicable rate-limit policy | `20, 20;w=60` indicates a quota of 20 requests per 60-second window. |
| `x-ratelimit-remaining` | The amount of rate limit credits left for the current window            | `19` indicates 19 requests remaining.                                |
| `x-ratelimit-reset`     | The number of seconds until the rate limit window resets.               | `32` indicates that the window resets in 32 seconds.                 |

When the remaining allowance reaches zero or a request receives `HTTP 429`, pause requests until the reported reset time. Add a small random delay before retrying to avoid synchronized requests.

These values are snapshots, not guaranteed allowances: other requests sharing the quota may consume capacity.