HTTP Status Codes Explained
Complete guide to HTTP status codes — what 200, 404, 500 mean and when to use each.
HTTP status codes tell clients whether a request succeeded, failed, or needs further action. Every API response includes a 3-digit status code in the first line of the HTTP response.
Status code categories
- 1xx Informational — request received, processing continues
- 2xx Success — request completed successfully
- 3xx Redirection — client must take additional action
- 4xx Client Error — problem with the request
- 5xx Server Error — server failed to fulfill a valid request
Most common codes
- 200 OK — standard success response
- 201 Created — new resource created
- 301 Moved Permanently — permanent redirect
- 400 Bad Request — malformed request syntax
- 401 Unauthorized — authentication required
- 403 Forbidden — authenticated but not allowed
- 404 Not Found — resource does not exist
- 429 Too Many Requests — rate limit hit
- 500 Internal Server Error — unexpected server failure
- 503 Service Unavailable — server temporarily down