HTTP Status Code Reference
Look up what any HTTP status code means, from 200 to 500 and everything between.
What the server is telling you
Every web response carries a status code, and knowing them turns debugging from guesswork into diagnosis. This is a reference to what each code means, grouped by family: the 2xx successes, the 3xx redirects, the 4xx client errors where the request was wrong, and the 5xx server errors where the server failed. Look up a code and see exactly what it signals.
Find a status code and read what it means and when it is used.
The families tell you where to look
The first digit is the most useful thing about a status code, because it tells you whose problem it is. A 4xx means the request was at fault — a 404 for a missing resource, a 401 or 403 for authentication and permission issues — so you look at what was sent. A 5xx means the server failed, so the fix is server-side, not in your request. Reading the family first points you at the right half of the problem before you even check the specific number.
Questions & answers
What do the status code families mean?
2xx is success, 3xx is redirection, 4xx is a client error where the request was wrong, and 5xx is a server error.
What is the difference between 401 and 403?
401 means you are not authenticated — you need to log in; 403 means you are authenticated but not allowed to access the resource.
Is anything uploaded?
No. It is a reference that runs in your browser.