How to Handle API 429 Errors: Rate Limits, Retry Logic, and Safe Strategies

An HTTP 429 error indicates a server has rejected a request due to rate or usage limits, but the exact cause can vary widely across providers. RFC 6585 defines the status as 'too many requests,' yet it does not standardize how limits are counted or how long a client should wait before retrying. Responses may include a Retry-After header, though this is not guaranteed, and limits can apply at the level of a single resource, API key, project, or entire organization. Safe retry strategies involve reading the full response body and headers, respecting any Retry-After value as a minimum delay, and adding random jitter to avoid synchronized retry storms. For requests with side effects, developers must first confirm whether the original request completed before issuing another attempt, and repeated retries without addressing the root cause can worsen the problem.