429 Too Many Requests
The client has sent too many requests in a given amount of time (rate limiting).
| Class | Client error (4xx) |
|---|---|
| Defined in | RFC6585 |
| Cacheable by default | No, unless explicit freshness headers allow it |
Common causes
- Exceeding an API's rate limit.
- Too many login attempts, or crawlers that are too aggressive.
What to do
Slow down and retry after the delay given in the Retry-After header, if present. Use exponential backoff in clients.
Related codes
- 503 Service Unavailable: The server is not ready to handle the request, often because of overload or maintenance.
- 403 Forbidden: The server understood the request but refuses to authorize it.
- 408 Request Timeout: The server timed out waiting for the request to be sent in full.