About the HTTP Status Code Lookup
Every web response comes with a three-digit status code, and the number tells you whether a request worked, moved or failed. This lookup lets you search the common codes by number, by group, such as 4xx, or by a word like redirect, cache or timeout. Each result gives the name and a short plain-English meaning, and the large result shows which group the code belongs to: informational, success, redirection, client error or server error. It is a quick reference for developers, testers, SEO work and anyone puzzled by an error page. Nothing is sent anywhere.
Updated October 2026
How to use the HTTP Status Code Lookup
- 1Type a code such as 404, a group such as 4xx, or a word such as redirect.
- 2Read the main result and the meaning.
- 3Scroll the list of matching codes below it.
- 4Use the Copy button to copy all matches.
- 5Change the search to look up another code.
The five groups
The first digit gives the family. 1xx codes are rare interim notices. 2xx codes mean the request worked, with 200 OK the most common. 3xx codes tell the client to look somewhere else. 4xx codes mean the client asked for something the server cannot or will not give. 5xx codes mean the server failed to do a valid request.
Knowing the family is often enough to tell where to look: a 4xx points at the request or the address, a 5xx points at the server.
- 1xx Informational
- 2xx Success
- 3xx Redirection
- 4xx Client error
- 5xx Server error
Codes that come up most
200 OK, 201 Created and 204 No Content for success. 301, 302, 304, 307 and 308 for redirects and caching. 400, 401, 403, 404, 405, 410, 429 for client errors. 500, 502, 503 and 504 for server errors. Searching by word is useful when you only remember part of the name, for example gateway or timeout.
Using the lookup when debugging
Open your browser's developer tools, find the failing request on the network tab and note its status. Search it here for the meaning, then check the matching side: the address and headers for a 4xx, or the server logs for a 5xx. For rate limits, the 429 entry explains why waiting a little and retrying is the right response. Status codes show up while you debug web calls. Use the JSON Validator for a broken response body, the URL Encoder & Decoder for a request address with odd characters, and the Base64 Encoder & Decoder for basic-auth style headers.
Features
- Search by number, group or word
- Plain-English meaning for each code
- Shows the group of the code
- Covers the codes you meet in practice
- Copy the results
- Works offline in your browser
Frequently asked questions
What does a 404 status code mean?
The server could not find the page or file you asked for. It is a client error: the address is wrong, the page was removed or it never existed.
What is the difference between 301 and 302?
A 301 says the page has moved permanently, so browsers and search engines should use the new address from now on. A 302 says the move is temporary, so the original address should still be used in future.
What does 500 Internal Server Error mean?
The server hit an unexpected problem and could not complete the request. It is a general error on the server side, so the cause is in the site's code or setup, not in your browser.
What do the groups 1xx to 5xx mean?
1xx is informational, 2xx means success, 3xx means redirection, 4xx means the request had a problem and 5xx means the server failed.
What is the difference between 401 and 403?
401 means you are not authenticated: you have to log in or send valid credentials. 403 means the server knows who you are but you are not allowed to use that resource.
Why do search engines care about status codes?
They use them to decide what to index. A 200 means the page can be indexed, a 301 passes the signal to the new address, a 404 or 410 removes the page over time, and repeated 5xx errors can slow crawling.