HTTP Status Code Reference
1xx Informational
The server has received the request headers and the client should proceed to send the request body.
The server is switching protocols as requested by the client.
2xx Success
The request has succeeded.
The request has been fulfilled and a new resource has been created.
The request has been accepted for processing, but processing is not complete.
The server successfully processed the request but returns no content.
The server is delivering only part of the resource due to a range header.
3xx Redirection
The resource has been permanently moved to a new URL.
The resource has been temporarily moved to a different URL.
The response can be found at a different URI using GET.
The resource has not been modified since the last request.
The request should be repeated with the same method at a different URI.
The resource has been permanently moved; future requests should use the new URI.
4xx Client Error
The server cannot process the request due to client error (e.g., malformed syntax).
Authentication is required and has failed or has not been provided.
The server understood the request but refuses to authorize it.
The requested resource could not be found on the server.
The HTTP method is not allowed for the requested resource.
The server cannot produce a response matching the Accept headers.
The server timed out waiting for the request.
The request conflicts with the current state of the server.
The resource is no longer available and will not be available again.
The request entity is larger than the server is willing to process.
The URI provided was too long for the server to process.
The media format of the requested data is not supported.
The request was well-formed but unable to be followed due to semantic errors.
The user has sent too many requests in a given amount of time.
5xx Server Error
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 received an invalid response from an upstream server.
The server is temporarily unable to handle the request.
The server did not receive a timely response from an upstream server.
What Are HTTP Status Codes?
HTTP status codes are three-digit numbers returned by a web server in response to a client's request. Defined by the IETF in RFC 9110 and related standards, these codes indicate whether a request was successfully completed, redirected, or resulted in an error. Every time you visit a website, your browser receives a status code — a 200 means success, while a 404 means the requested page was not found. Understanding these codes is essential for anyone working with websites, APIs, or network infrastructure.
How to Use
Type a status code number, name, or keyword to filter the list. All HTTP status codes are shown by default, grouped by category. You can search by the numeric code (e.g., 404), the status name (e.g., Not Found), or a descriptive keyword (e.g., redirect).
Status Code Categories
1xx: Informational responses indicating the request was received and processing continues. 2xx: Successful responses confirming the request was received, understood, and accepted. 3xx: Redirection messages telling the client to take additional action. 4xx: Client error responses indicating the request contains bad syntax or cannot be fulfilled. 5xx: Server error responses indicating the server failed to fulfill a valid request.
Common Use Cases
- API development and debugging — quickly identify why requests are failing
- Server monitoring and alerting — understand error patterns in production logs
- Web development — diagnose issues with redirects, authentication, and resource loading
- SEO analysis — check for broken links, improper redirects, and crawl errors
- Learning and reference — study the HTTP protocol and REST API conventions
Tips
The most common codes you'll encounter are 200 (OK), 301 (Moved Permanently), 302 (Found, temporary redirect), 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404 (Not Found), and 500 (Internal Server Error). When debugging API issues, always check the response body alongside the status code for detailed error messages.
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