About HTTP Status Codes
HTTP Status Codes turns a numeric response code into its standard reason phrase, so a line in an access log or a monitoring alert stops being an opaque three-digit number. Entering a code returns the matching status and its name — the classic 404 and its meaning, for example.
The table it draws on is a curated set of the codes that appear in practice rather than the complete registry. It covers the informational, success, redirect, client-error and server-error codes you are most likely to meet, including the ones that cause the most confusion in day-to-day debugging, such as the distinction between a redirect that preserves the request method and one that does not.
Anything outside that set is not treated as a mistake. If the code is not in the table, the tool lists the codes it does know, which turns the lookup into a browsable reference rather than a dead end — useful when you are trying to work out which of several similar codes actually applies to the situation in front of you.
How to use HTTP Status Codes
- 1 Type the three-digit status code you want to identify.
- 2 Read the reason phrase returned for that code.
- 3 If the code is not listed, read the reference list to find the nearest matching one.
Frequently asked questions
Does it cover every code in the registry?
No — it is a curated set of the ones that turn up in real traffic and debugging. Less common or vendor-specific codes will not be found, and the tool responds by listing what it does cover rather than returning nothing.
What is the difference between a 301 and a 307 redirect?
A 301 tells clients and search engines the move is permanent and may allow the request method to change; a 307 preserves the original method exactly, which matters when the request was a POST. Use 307 when the method must survive the redirect.
What does 418 mean?
It is a deliberate joke code about teapots, defined as an April Fools extension and never issued by real servers. It appears in the table for the same reason it appears in so many status-code lists.
Should I be worried about 4xx codes on my site?
Some of them indicate real problems and others are normal. A 404 on a page that no longer exists is expected; a 404 on a link in your own navigation is a defect. A 429 means a client is being rate limited, which is a policy working as designed.
Free, online, and private
Free to use
HTTP Status Codes is completely free. There is no account to create, no login, and no hidden charge or usage limit.
Runs online in your browser
It is a free online tool that runs entirely in your browser. Nothing to download or install — open the page and start using it right away.
Your data stays private
All processing happens locally on your device. Your input is never uploaded, stored, or tracked, so it never leaves your browser.
How HTTP Status Codes behaves in detail
These are the specifics of this implementation — the exact ranges, defaults and fixed settings you are working with.
| Parameter | Value |
|---|---|
| Table coverage | 25 codes — 1 in the 1xx class, 4 in 2xx, 4 in 3xx, 11 in 4xx and 5 in 5xx |
| Lookup key | the trimmed input string matched exactly against the code, with no numeric coercion |
| Hit output | one line: the code, a space, then the stored reason phrase |
| Miss output | the fallback prints "Unknown code." followed by every row of the table |
| Live behaviour | recomputed on each keystroke, so a half-typed 40 already falls to the full-list fallback |
| Stored example | 418 resolves to "I'm a teapot" — the list is a hand-written map, not a generated one |
Compiled from the implementation of this tool and checked against it by itoolnet.
What HTTP Status Codes does not do
Knowing the edges of a tool saves more time than another list of its features. These are the cases where it will not do what you might expect.
- The map holds 25 codes and skips several real ones: 203, 206, 300, 303, 308, 406, 411, 413, 416, 426 and 451 are all missing, so those inputs return the fallback plus the whole list instead of an answer.
- No class context is given. The reason phrase appears alone, so nothing tells you that a 4xx is the caller's fault and a 5xx the server's, and there is no description of the cause or of what to do about it.
- The lookup only runs in one direction. Typing a phrase such as Not Found never resolves to 404, and an input that carries a suffix or decimal (404; or 404.0) does not match the exact-string key.
Tested and documented by itoolnet, the team that builds and maintains this site.