HTTP Status Codes

What is HTTP Status Codes?

HTTP Status Codes provides a comprehensive searchable reference for all standard HTTP response codes grouped by class — 1xx informational, 2xx success, 3xx redirection, 4xx client error, and 5xx server error. Each code includes its official name, a plain-language explanation, common causes, and troubleshooting guidance. The reference covers codes from HTTP/1.1 (RFC 7231), WebDAV extensions, and common non-standard codes used by cloud providers.

API designers defining response contracts, backend developers handling error cases, and frontend developers building robust fetch error handling. The tool runs entirely in your browser — your data never leaves your device.

How to Use HTTP Status Codes

1. Browse status codes by category using the tabbed navigation — 1xx through 5xx
2. Use the search bar to find a specific code by number or keyword
3. Click on any status code to expand its detailed description and troubleshooting notes
4. Review the common causes section to understand when your server or API might return that code
5. Reference the suggested response headers and body format for each status code

Common Use Cases

• Quickly looking up the meaning of a 422 Unprocessable Entity or 429 Too Many Requests during API debugging
• Understanding the difference between 301 Moved Permanently and 302 Found for correct redirect implementation
• Troubleshooting 502 Bad Gateway errors from reverse proxies like Nginx or AWS ALB
• Educating junior developers about proper status code usage in REST API design
• Choosing the correct error code to return from a custom API endpoint for standards compliance

Pro Tips

• Use 204 No Content instead of 200 with an empty body for DELETE endpoints — it explicitly signals that no response body is expected
• Return 409 Conflict for duplicate resource creation rather than 400 Bad Request — it gives clients more precise information about the error
• Remember that 304 Not Modified saves bandwidth by telling the client to use its cached copy — always implement ETag or Last-Modified headers for cacheable responses

Why Use This Tool?

• Privacy-first: All processing happens locally in your browser. No data is transmitted to any server.
• No installation required: Works in any modern browser on desktop or mobile.
• Completely free: No account, no credit card, no usage caps.
• Fast and reliable: Powered by modern Web APIs for near-instant results.

Related Concepts

Learn more about related topics: RFC 7231, REST API design, Content negotiation, Cache-Control.

Frequently Asked Questions