HTTP Status Codes — Searchable Reference
Look up any HTTP status code — its meaning, its class, and the friendly explanation behind the jargon.
—
What this tool does
It is a searchable table of HTTP status codes — the three-digit numbers a server returns to say how a request went. Type a code, a word from its name, or a phrase from its meaning, and the list filters to what you need. It explains each in plain language rather than restating the spec.
The five classes
| Class | Meaning |
|---|---|
| 1xx | Informational — the request was received and is being processed. |
| 2xx | Success — the request was received, understood and accepted. |
| 3xx | Redirection — further action is needed to complete the request. |
| 4xx | Client error — the request contains bad syntax or cannot be fulfilled. |
| 5xx | Server error — the server failed to fulfil a valid request. |
The codes people actually meet
In day-to-day work a handful dominate: 200 for a good response, 301/302 for redirects, 304 for a cache that is still fresh, 400/401/403/404 for the client-side failures, 429 for rate limiting, and 500/502/503/504 for the server-side ones. Learning to read them turns a vague "the site is broken" into a precise statement of whose end the problem is on.
How to choose one when building
Return the most specific code that is true. A missing page is 404; a deleted one is 410; a request for something you know exists but the caller may not see is 403, not 404, unless you are deliberately hiding its existence. A successful create is 201, not 200. Specific codes make logs readable and APIs predictable — a caller can branch on the code instead of parsing an error message.
Frequently asked questions
What is an HTTP status code?
A three-digit number a web server returns with every response to say how the request went. The first digit names the class: 2xx means success, 3xx means a redirect, 4xx means the client did something wrong, and 5xx means the server did. The two digits after that name the specific case.
What is the difference between 401 and 403?
401 Unauthorized means you are not authenticated — you have not logged in, or your credentials failed. 403 Forbidden means you are authenticated but not allowed: the server knows who you are and refuses anyway. The names are confusing (401 is really "unauthenticated"), but the distinction is real.
What is the difference between 301 and 302?
301 says the resource has moved permanently, so clients and search engines should update their records to the new URL. 302 says it is a temporary move, so they should keep requesting the old URL. 307 and 308 are the same two, but guarantee the request method is preserved.
When should I use 404 vs 410?
404 Not Found says the resource is not here — but it might come back. 410 Gone says it was here and is permanently removed. 410 is more definitive and search engines drop the page faster, so use it when you have deliberately and permanently deleted something.
What does 5xx mean for me as a user?
It means the problem is on the server, not with your request — there is usually nothing you can do but retry. 502 and 504 are common on a misconfigured proxy or an overloaded backend; 503 often means the service is briefly down for maintenance or too busy.
Is this tool a lookup or does it call a URL?
A lookup only. It is a reference table you can search — paste a code and read its meaning. It never makes a request to any URL.
Go deeper
Longer explanations of the problems this tool solves:
Sources
- RFC 9110 — HTTP Semantics (status codes).
- IANA HTTP Status Code Registry.
Everything runs in your browser — nothing you type is uploaded.