HTTP Status Code Reference & Lookup

When you browse the web, your browser constantly communicates with servers using HTTP (Hypertext Transfer Protocol). Every time a request is made, the server responds with a three-digit status code. Most of the time, this code is 200 OK, which happens invisibly behind the scenes.

However, when something goes wrong, the server returns an error code (like 404 or 500). Use this tool to instantly look up exactly what a specific status code means, why the server sent it, and how you can begin debugging the underlying network or application issue.

How it works

HTTP status codes are standardized by the Internet Engineering Task Force (IETF), though modern CDNs like Cloudflare have introduced their own custom codes (the 52x series) to explain edge-caching errors.

Status codes are strictly grouped into five distinct classes based on their starting digit:

• 1xx (Informational): The request was received, and the process is continuing.
• 2xx (Successful): The action was successfully received, understood, and accepted. (e.g., 200 OK)
• 3xx (Redirection): Further action must be taken in order to complete the request. (e.g., 301 Redirect)
• 4xx (Client Error): The request contains bad syntax or cannot be fulfilled. The error is likely caused by the user or their browser. (e.g., 404 Not Found, 403 Forbidden)
• 5xx (Server Error): The server failed to fulfill an apparently valid request due to a fatal backend crash, overload, or misconfiguration. (e.g., 500 Internal Error, 502 Bad Gateway)

By entering a specific code in the lookup box above, the tool will instantly fetch its exact definition and typical troubleshooting steps without requiring you to scour technical documentation.

Frequently asked questions