← All status codes4xx – Client Error

HTTP 429 – Too Many Requests

The client has sent too many requests in a given time window (rate limiting).

Common use case

The standard response for API rate limiting, usually paired with a Retry-After header telling the client how long to back off.

Example

HTTP/1.1 429 Too Many Requests
Retry-After: 30

{"error":"Rate limit exceeded"}

History

Standardised in RFC 6585 (2012) - before this, rate-limited APIs had to improvise using 403 or 503.

Did you know?

It is one of the most-monitored codes for API integrators, since a spike in 429s is usually a sign a client needs to add exponential backoff.