HTTP Status Code Lookup
Search HTTP status codes from 100 to 599 with name, category and clear description. Filter by number or text — a fast, free, private in-browser reference.
The server has received the request headers and the client should proceed to send the request body.
The requester has asked the server to switch protocols and the server has agreed to do so.
The server has received and is processing the request, but no response is available yet (WebDAV).
Used to return some response headers before the final HTTP message, allowing preloading of resources.
The request succeeded. The meaning of success depends on the HTTP method used.
The request succeeded and a new resource was created as a result.
The request has been received but not yet acted upon, typically for asynchronous processing.
The returned metadata is from a local or third-party copy rather than the origin server.
The request succeeded but there is no content to send in the response body.
Tells the client to reset the document view that sent the request.
The server is delivering only part of the resource due to a range header sent by the client.
Conveys information about multiple resources where several status codes could apply (WebDAV).
Members of a DAV binding have already been enumerated and are not being included again.
The server has fulfilled a GET request and the response represents the result of instance-manipulations.
The request has more than one possible response; the user or agent should choose one of them.
The requested resource has been permanently moved to a new URL given in the Location header.
The resource resides temporarily under a different URL; keep using the original URL for future requests.
The response can be found at another URL and should be retrieved with a GET request.
The cached copy is still valid; the client can reuse it without re-downloading the resource.
The resource is temporarily at another URL and the same HTTP method must be reused.
The resource is permanently at another URL and the same HTTP method must be reused.
The server cannot process the request due to a client error such as malformed syntax.
Authentication is required and has failed or has not yet been provided.
Reserved for future use; sometimes used by APIs to signal a billing or quota problem.
The server understood the request but refuses to authorize it.
The server cannot find the requested resource; the URL is not recognized.
The request method is known by the server but is not supported by the target resource.
The resource cannot produce a response matching the Accept headers sent by the client.
The client must first authenticate itself with the proxy.
The server timed out waiting for the request from the client.
The request conflicts with the current state of the target resource.
The resource is no longer available and this condition is expected to be permanent.
The server refuses the request because it lacks a defined Content-Length header.
One or more conditions given in the request header fields evaluated to false.
The request entity is larger than the limits defined by the server.
The URI requested by the client is longer than the server is willing to interpret.
The media format of the requested data is not supported by the server.
The range specified by the Range header cannot be fulfilled.
The expectation given in the Expect request header could not be met by the server.
An April Fools' joke code; the server refuses to brew coffee because it is a teapot.
The request was directed at a server that is not able to produce a response.
The request was well-formed but could not be followed due to semantic errors (WebDAV).
The resource that is being accessed is locked (WebDAV).
The request failed because it depended on another request that failed (WebDAV).
The server is unwilling to risk processing a request that might be replayed.
The client should switch to a different protocol given in the Upgrade header.
The origin server requires the request to be conditional to avoid lost updates.
The user has sent too many requests in a given amount of time (rate limiting).
The server refuses to process the request because its header fields are too large.
The resource is unavailable due to legal demands such as censorship or takedown.
The server encountered an unexpected condition that prevented it from fulfilling the request.
The server does not support the functionality required to fulfill the request.
The server, acting as a gateway, received an invalid response from an upstream server.
The server is not ready to handle the request, often due to maintenance or overload.
The server, acting as a gateway, did not get a response in time from an upstream server.
The HTTP version used in the request is not supported by the server.
The server has an internal configuration error in transparent content negotiation.
The server is unable to store the representation needed to complete the request (WebDAV).
The server detected an infinite loop while processing the request (WebDAV).
Further extensions to the request are required for the server to fulfill it.
The client needs to authenticate to gain network access, e.g. a captive portal.
What is the HTTP Status Code Lookup?
The ByteTools HTTP Status Code Lookup is a searchable reference for every common HTTP response code from 100 to 599.
- Covers common status codes across the 100-599 range
- Name, category and plain-English description for each
- Instant filtering by number or text
- Colour-coded by class: 1xx to 5xx
- Loads instantly and works offline
- 100% client-side — nothing is uploaded
How to use the HTTP Status Code Lookup
- 1
Type a status code number or a keyword into the search box.
- 2
Browse the filtered list of matching codes.
- 3
Read the name, category and description for each code.
- 4
Use the colour-coded category to see the response class at a glance.
About the HTTP Status Code Lookup
The ByteTools HTTP Status Code Lookup is a searchable reference for every common HTTP response code from 100 to 599. Each entry shows the code, its official name, the category it belongs to and a plain-language description of what it means.
Filter the list by typing a number like 404 or a phrase like redirect, and the results narrow instantly. Codes are colour-coded by class — 1xx informational, 2xx success, 3xx redirection, 4xx client error and 5xx server error — so you can see at a glance whether a response is good news or a problem.
The whole reference is bundled into the page and searched locally, so it loads instantly and works offline. It is the quick answer you need when debugging an API, a fetch call or a server log.
Frequently asked questions
What do HTTP status codes mean?
An HTTP status code is a three-digit number a server returns to describe the outcome of a request. The first digit gives the class — 2xx means success, 3xx redirection, 4xx a client error and 5xx a server error — and the full code pinpoints the specific situation.
What is the difference between a 401 and a 403?
A 401 Unauthorized means authentication is required or has failed, so the server does not know who you are. A 403 Forbidden means you are authenticated but not allowed to access the resource. In short, 401 is about identity and 403 is about permission.
What does a 404 error mean?
404 Not Found means the server could not find a resource at the requested URL. The address may be mistyped, the page may have been moved or deleted, or the link pointing to it may be broken.
What are 5xx errors?
5xx codes indicate the server failed to fulfil a valid request. Common ones are 500 Internal Server Error for an unexpected fault, 502 Bad Gateway and 504 Gateway Timeout for upstream problems, and 503 Service Unavailable during maintenance or overload.
Is 301 or 302 better for a redirect?
Use 301 Moved Permanently when a resource has a new permanent home, as search engines transfer ranking to the new URL. Use 302 Found (or 307) for a temporary redirect where the original URL should keep being used in future.
Does this tool look codes up online?
No. The full list of status codes ships with the page and is searched in your browser, so results are instant and the tool keeps working without a connection.
Guides for HTTP Status Code Lookup
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