What do the HTTP status code classes 1xx to 5xx mean?

Codes are grouped by their first digit: 1xx informational, 2xx success, 3xx redirection, 4xx client errors (the request is at fault), and 5xx server errors (the server failed to fulfil a valid request).

What is the difference between a 301 and a 302 redirect?

301 means the resource moved permanently, so browsers and search engines update to the new URL; 302 is temporary and clients should keep requesting the original URL. When the request method must be preserved, use 308 and 307 instead.

What is the difference between 401 Unauthorized and 403 Forbidden?

401 means the request lacks valid authentication credentials, so logging in or fixing the token may help; 403 means the server knows who you are but refuses access, and authenticating again will not change the result.

Is this reference free and does it work offline?

Yes. It is completely free with no account required, and because the whole list ships with the page it keeps working offline once loaded.

Is anything I search sent to a server?

No. Searching and filtering run entirely in your browser; the query text never leaves your device and nothing is uploaded or tracked.

HTTP Status Codes Reference

Searchable reference for HTTP response status codes

1xx · Informational

2xx · Success

3xx · Redirection

4xx · Client Error

5xx · Server Error

FAQ

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