HTTP Status Codes
Search every HTTP status code from 100 to 599 with meanings and RFCs, plus unofficial nginx, Cloudflare, IIS and AWS codes like 499 and 522.
π Runs entirely in your browser β nothing is uploadedWhat HTTP Status Codes does
HTTP Status Codes is a searchable reference for response codes in the 100 through 599 range. It helps when debugging API calls, writing documentation, choosing a response for a new endpoint, reading logs, reviewing gateway behavior, or explaining a failure to another developer. Each entry includes the numeric code, reason phrase, category, the RFC that defines it, and a short description of what the response usually means. Filter chips narrow the list to informational, success, redirect, client-error or server-error codes.
Real traffic also contains codes that no standard defines. A 499 in an nginx log means the client gave up before the server answered; a 522 from Cloudflare means the origin did not complete the TCP handshake; a 460 or 561 comes from an AWS load balancer. These unofficial codes are listed in their own group together with the product that emits them, so you can quickly tell whether a failure came from your application, a proxy or a CDN. Clicking a result copies the code and phrase for issue comments, docs, tests, or endpoint notes.
Private browser-based workflow
All processing happens inside your browser with client-side JavaScript. The list is embedded directly in the page rather than fetched from a service, which makes it fast and available even when you are working offline or debugging network problems, and nothing you type is sent anywhere.
Practical tips
Status codes are part of an API contract, so choose them deliberately. Use 400-level responses when the client can change the request, 500-level responses when the server failed to fulfill a valid request, and 300-level responses when the client should look elsewhere. Authentication and authorization failures are often confused: 401 usually means authentication is required or invalid, while 403 means the authenticated caller is not allowed. Prefer 422 for validation errors in a well-formed body, 409 for state conflicts and 429 with a Retry-After header for rate limiting. Never return unofficial codes from your own API β clients and libraries may not understand them.
How to use
- Search or filterType a code, phrase or keyword, or pick a class such as 4xx or Unofficial.
- Scan resultsReview each code's meaning, category and defining RFC or vendor.
- Copy detailsClick a card to copy the code and phrase for docs or debugging notes.