Search every standard HTTP status code by number, class like 4xx, or keyword such as redirect. Each result explains what the code means in one line.
Runs entirely in your browser — your data never leaves your device.
How to use HTTP Status Code Reference
What it does & when you need it
HTTP replies to every request with a three-digit status code, and knowing what
each one means is the fastest way to tell whether a problem is yours or the
server's. This is a searchable reference for every standard code from 100 to
511, each with a one-line explanation. The whole table ships with the page, so
lookups are instant and work offline, and nothing you type is sent anywhere.
Reach for it when you hit an unfamiliar code in a log, an API response, or a
browser dev-tools network tab and want a plain-language answer without leaving
your workflow.
How to use
Type a number for an exact code (404), a shorter number for a prefix (40
lists 400–409), or a class such as 4xx to see a whole family.
Or type a word like redirect or timeout to search names and descriptions.
Clear the box to browse every code grouped by class. Copy results with
Copy or Ctrl/Cmd + Enter.
Things worth knowing
The first digit assigns blame.1xx is informational, 2xx is success,
3xx is redirection, 4xx is a client error (the request was wrong), and 5xx
is a server error (the request was fine, the server failed). That single digit
usually tells you which side to debug first.
401 and 403 are not the same.401 Unauthorized means you are not
authenticated, so credentials may fix it. 403 Forbidden means you are known but
not allowed, so retrying as the same user will not.
Redirects differ in method handling.301 and 302 let old clients switch
the request to GET, while 307 and 308 guarantee the original method is kept
— which matters after a POST. To inspect the headers behind a code, use the
HTTP header checker, or decode a
MIME type.
Examples
Look up one code
404
Returns 404 Not Found with a one-line explanation of what it means.
List a whole class
5xx
Shows every server-error code from 500 to 511 at once.
Search by keyword
redirect
Finds the redirection codes whose name or description mentions redirect.
Frequently asked questions
How do I search for a status code?+
Type a number for an exact match (404), a shorter number to match a prefix (40 lists 400 to 409), a class like 4xx or 5xx to list a whole family, or a word like "redirect" or "timeout" to search the names and descriptions. Clearing the box lists every code grouped by class.
What do the five status classes mean?+
1xx is informational, 2xx means success, 3xx is redirection, 4xx is a client error where the request was wrong, and 5xx is a server error where the request was fine but the server failed. The first digit alone tells you who is likely at fault.
What's the difference between 401 and 403?+
401 Unauthorized means you are not authenticated — no valid credentials were supplied, so logging in may help. 403 Forbidden means you are authenticated but not allowed; the server knows who you are and still refuses, so retrying with the same identity will not work.
When should I use 301 versus 302 or 308?+
Use 301 Moved Permanently when a URL has permanently changed so clients and search engines update their links. Use 302 Found for a temporary move. Prefer 308 and 307 when you must guarantee the HTTP method is preserved, since older clients may switch 301 and 302 to GET.
Are these codes memorized or looked up locally?+
The full table ships with the tool, so searching is instant and works offline. Nothing you type is sent to a server; the filtering runs entirely in your browser.