Backend Development › API Design

429 Too Many Requests

The status returned when a client goes over a rate limit.

Also known as: Too Many Requests, rate limit error

A 429 Too Many Requests response means the client has sent too many requests in a given period, and the server is refusing more until the window resets. It’s how a rate limit shows up to the client.

HTTP/1.1 429 Too Many Requests
Retry-After: 30
Content-Type: application/json

{"error": "rate_limited", "message": "Too many requests. Try again in 30 seconds."}

The Retry-After header tells the client how long to wait, in seconds or as a date. Include it when you can, because clients that know the wait time can pause instead of guessing.

On the frontend, handle a 429 by pausing and showing a helpful message, not by retrying straight away. A common pattern is exponential backoff with jitter, so many clients don’t all retry at the same moment.

The classic mistake is retrying immediately in a tight loop. Each retry is another request, so the client keeps hitting the limit and makes the server’s load worse. A 429 is a signal to slow down, not an error to hammer through. See HTTP 4xx responses for how this status fits with the other client-error codes.