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

# Rate Limits for the Trassets Data API

> Trassets Data API allows 500 requests per hour per API key. Learn how to handle 429 responses and minimize unnecessary requests with delta sync.

The Trassets Data API enforces a rate limit of **500 requests per hour per API key**. Every request counts toward this limit, including retries and polling calls. When you exceed the limit, the API returns a 429 status code and you must wait until the current hour window resets before making additional requests.

## 429 Response Example

When you hit the rate limit, the API responds with an RFC 7807 problem JSON body:

```json theme={null}
{
  "type": "about:blank",
  "title": "Too Many Requests",
  "status": 429,
  "detail": "Rate limit exceeded: 500 per 1 hour",
  "instance": "/property/properties"
}
```

## Handling Rate Limits

Every response includes `X-RateLimit-Limit` and `X-RateLimit-Remaining` headers so you can throttle proactively instead of waiting for a 429.

If you do receive a 429 response, use the `Retry-After` header instead of guessing a wait time:

1. Stop sending new requests immediately.
2. Read the `Retry-After` header — it gives the exact number of seconds until the current window resets. Wait at least that long before retrying.
3. Double the wait time on each subsequent retry if the 429 persists.
4. Resume normal request spacing once requests succeed again.

For long-running sync jobs, spread requests evenly across the hour instead of bursting at the start. For example, a job that issues one request every 7 seconds will stay safely under the 500 request limit.

<Tip>
  Use the [Delta Sync endpoint](/guides/delta-sync) (`GET /changes`) to poll for changed tables instead of repeatedly querying every endpoint. This lets you skip endpoints that have not changed since your last sync, reducing your overall request volume.
</Tip>