> ## Documentation Index
> Fetch the complete documentation index at: https://docs.isend.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Rate limit

> Understand rate limits and how to increase them when using the isend.ai API.

The isend.ai API uses response headers to indicate your current rate limit status, following the IETF standard:

| Header name           | Description                                                         |
| --------------------- | ------------------------------------------------------------------- |
| `ratelimit-limit`     | Maximum number of requests allowed within a window.                 |
| `ratelimit-remaining` | How many requests you have left within the current window.          |
| `ratelimit-reset`     | How many seconds until the limits are reset.                        |
| `retry-after`         | How many seconds you should wait before making a follow-up request. |

The default rate limit is **2 requests per second**. Trusted senders may request an increase.

If you exceed the rate limit, the API will return a `429` response error. To review these events, filter for status `429` in your isend.ai logs.

### Tips to Avoid Rate Limits

* Implement a queueing system for API calls.
* Throttle or stagger requests to prevent bursts.
* Avoid sending requests concurrently unless necessary.
* Monitor your usage through headers in API responses.

If you have unique needs or expect higher traffic, contact our support team to request a rate increase.