Tools
HTTP Status Codes
The HTTP status codes reference provides a searchable list of all standard HTTP response codes defined by IANA, including their official name, a plain-English explanation, and typical usage context. The codes are organized by class — informational, success, redirection, client error, and server error. This is an essential daily reference for backend developers, API designers, and web operations teams.
What are HTTP Status Codes?
HTTP status codes are three-digit numbers returned by a web server in response to a client's request. The first digit indicates the response class: 1xx for informational responses, 2xx for success, 3xx for redirection, 4xx for client errors, and 5xx for server errors. Status codes are defined in RFC 7231 and subsequent RFCs and are a fundamental part of the HTTP protocol. Every API call, page load, and web request results in a status code that both browsers and programmatic clients can act on.
How does it work?
Enter a status code number or keyword in the search field to find the matching code instantly. Each entry shows the official IANA name, the RFC that defines it, a description of when it is used, and notes on how clients should handle it. You can also browse by class using the category tabs. The tool covers all IANA-registered codes as well as widely used unofficial codes like 429 Too Many Requests and 451 Unavailable For Legal Reasons.
Typical Use Cases
- Looking up the correct status code to return from a REST API endpoint
- Debugging an unexpected response code from a third-party API
- Verifying redirect chain behavior during SEO audits
- Documenting API responses in OpenAPI / Swagger specifications
Step-by-step Guide
- Step 1: Type a status code number or keyword into the search field.
- Step 2: Read the official name and description for the matching code.
- Step 3: Check the notes on appropriate client handling behavior.
- Step 4: Reference the RFC link for the authoritative specification.
Example
Input
404
Output
404 Not Found — The server cannot find the requested resource. The URL is not recognized.
Tips & Notes
- Use 422 Unprocessable Entity for validation errors in REST APIs, not 400 Bad Request, when the syntax is valid but the content is semantically wrong.
- Return 429 Too Many Requests with a Retry-After header when implementing rate limiting.
- Prefer 204 No Content over 200 OK when a successful action has no response body.
Frequently Asked Questions
What is the difference between 401 and 403?
401 Unauthorized means the client is not authenticated — credentials are missing or invalid. 403 Forbidden means the server understood the request and the client is authenticated, but does not have permission to access the resource.
When should I use 301 vs 302?
301 Moved Permanently tells clients and search engines to update their links permanently. 302 Found is a temporary redirect and search engines will not transfer SEO ranking to the new URL. Use 301 for permanent changes and 308/307 for preserving the HTTP method.
HTTP Status Codes
All HTTP status codes at a glance — with name, meaning, and category. Searchable and filterable.
Open Tool