// http 4xx · client error
HTTP 429 Too Many Requests
The client has sent too many requests (rate limited).
What HTTP 429 Too Many Requests means
429 Too Many Requests means the client has been rate-limited for sending too many requests in too short a window. The response often includes a `Retry-After` header telling you how long to wait before trying again.
Which category is it?
429 is a 4xx code — Client error. 4xx means the request has a problem the client must fix — bad syntax, missing authentication, or a resource that isn't there. It's the caller's responsibility.
Common causes
- Exceeding an API's rate limit
- A retry loop firing too aggressively
- Missing backoff between requests
How to fix it
- Respect the `Retry-After` header and back off
- Add exponential backoff and jitter to retries
- Cache responses to reduce request volume