HTTP Status Codes

Look up what HTTP status codes mean. It is completely free and very easy to use.

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Technical Overview: How HTTP Status Codes Works

HTTP Status Codes is an interactive reference and lookup tool covering all 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Errors), and 5xx (Server Errors) HTTP response status codes defined by IETF RFCs.

Catalogs standard HTTP status codes governed by RFC 7231, RFC 6585, RFC 7540 (HTTP/2), and RFC 9110 (HTTP Semantics). Explains HTTP header behaviors, cacheability, retry headers (`Retry-After`), and browser handling for each code.

Practical Examples & Usage

Lookup HTTP 429 Too Many Requests

Input:Code: 429

Output:

429 Too Many Requests (RFC 6585) | Type: Client Error | Meaning: Rate limit exceeded. Include `Retry-After` header indicating wait seconds.

Provides formal specification definition, error category, and recommended API response headers.

Real-World Applications & Use Cases

Selecting appropriate HTTP response status codes when designing REST APIs (e.g. 201 Created vs 202 Accepted).
Troubleshooting web application error codes (401 Unauthorized vs 403 Forbidden, 404 Not Found vs 410 Gone).
Diagnosing server infrastructure failures (502 Bad Gateway vs 504 Gateway Timeout behind reverse proxies).
Configuring correct SEO redirection codes (301 Permanent vs 302 Temporary vs 308 Permanent Redirect).

How to use HTTP Status Codes

Use the search bar to filter status codes by number (e.g., 404) or by keyword (e.g., "Not Found").
Click on any HTTP status code card to expand its detailed definition and standard usage cases.
Use the category filters to jump directly to 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), or 5xx (Server Error) codes.
Quickly copy the code or description for your API documentation.

Edge Cases & Limitations

•Certain proprietary codes (e.g. Cloudflare 520-527, Nginx 499) are platform-specific extensions outside official IETF RFCs.
•301 redirects are cached permanently by browsers; use 302 or 307 during testing to prevent accidental local cache lockouts.
•401 requires a `WWW-Authenticate` header in the response, whereas 403 indicates authentication succeeded but authorization was denied.

Recommended Best Practices

•Use 201 Created when a POST request successfully creates a new resource and return the new resource URL in a `Location` header.
•Use 422 Unprocessable Entity for schema validation failures where JSON syntax is valid but semantic data fails business rules.
•Always return informative error payloads (`{ "error": "...", "code": 404 }`) alongside HTTP error status codes.

Frequently Asked Questions

What is the difference between a 4xx and a 5xx error?

4xx errors indicate that the problem lies with the client (e.g., bad request, unauthorized, not found). 5xx errors indicate that the client made a valid request, but the server failed to fulfill it.

What is the most common HTTP status code?

HTTP 200 OK is the most common status code, indicating that a request has succeeded. HTTP 404 Not Found is the most common error code.

Are unofficial status codes included?

This tool focuses on the official IANA registry of HTTP status codes to ensure standard compliance, though some common unofficial codes (like Cloudflare's 520 series) may be referenced.

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