What do the HTTP status code classes mean?

1xx are informational, 2xx mean success, 3xx are redirects, 4xx are client errors (the request was wrong), and 5xx are server errors (the server failed to fulfil a valid request).

What is the difference between 401 and 403?

401 Unauthorized means authentication is missing or failed, so logging in may fix it. 403 Forbidden means the server understood who you are but still refuses access, so credentials will not help.

What is the difference between 301 and 302?

301 Moved Permanently tells clients and search engines the resource has a new permanent URL, so they update bookmarks and links. 302 Found is a temporary redirect — the original URL should still be used in future.

What does a 429 status code mean?

429 Too Many Requests means you have been rate-limited. Slow down and check the Retry-After response header, which says how long to wait before retrying.

When should an API return 404 versus 410?

404 Not Found means the resource is not here (and may exist later). 410 Gone means it existed but has been permanently removed, signalling clients to stop requesting it.

Is anything I search sent to a server?

No. The entire reference and search runs entirely in your browser — nothing you type is uploaded anywhere.

HTTP Status Codes Reference

HTTP status codes — searchable reference

A complete, searchable list of the HTTP status codes you hit while building and debugging APIs and websites, each grouped by class with a plain-English meaning. It is the fastest way to answer “what does this code mean?” without leaving your editor.

How it works

Every response carries a three-digit status code, and the first digit gives its class: 1xx informational, 2xx success, 3xx redirection, 4xx client error, 5xx server error. This reference lists the codes you actually encounter, organised into those five groups, each with its official name and a short description. Typing in the search box filters the whole table at once, matching the number, the name, or words in the meaning — so a search for redirect, 404, or rate all find the relevant rows.

Example

The codes you meet most often:

Code	Name	Meaning
200	OK	Request succeeded
301	Moved Permanently	Resource has a new permanent URL
401	Unauthorized	Authentication required or failed
403	Forbidden	Authenticated but not allowed
404	Not Found	No such resource
429	Too Many Requests	Rate limited; check Retry-After
500	Internal Server Error	The server failed unexpectedly
503	Service Unavailable	Temporarily down or overloaded

Search by number, name, or meaning to find the right code instantly. Everything runs in your browser; nothing is uploaded.