HTTP status code reference · Guide
HTTP Status Codes Lookup
An HTTP status code lookup tells you what a code means and which category it belongs to. This guide covers how the categories work and how to use a lookup while debugging.
Search by code or phrase
Type a code like 404 or a phrase like "not found" and the lookup shows the matching status with its meaning and group. It is faster than remembering every code by heart.
The five categories
1xx is informational, 2xx success, 3xx redirection, 4xx client errors and 5xx server errors. The first digit tells you whose problem it likely is — the request or the server.
Frequently asked questions
What is the difference between 4xx and 5xx?
4xx means the client request was at fault (bad input, missing auth, wrong URL); 5xx means the server failed to handle a valid request. The first digit points you in the right direction.
Ready to try it?
Open the free browser-based HTTP status code reference and apply what you just read — no sign-up, runs locally.
Open the HTTP status code reference tool