HTTP Status Code Reference
Searchable reference guide for all HTTP status codes
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⚙️ How It Works
Quickly locate codes by typing the exact 3-digit number or a descriptive word into the search bar. You can also filter exclusively by category (like 2xx or 4xx). Click on the external link icon to learn more on MDN.
❓ Frequently Asked Questions
What do the different categories mean?
Codes are grouped by their first digit: 1xx are Informational, 2xx mean Success, 3xx dictate Redirection, 4xx imply Client Errors (you did something wrong), and 5xx signify Server Errors (we did something wrong).
Are these official status codes?
Yes, our reference primarily covers standard status codes defined by the Internet Engineering Task Force (IETF) in RFCs like RFC 9110, alongside common unofficial codes used by major servers like Nginx or Cloudflare.
When should I use 400 vs 422?
Use `400 Bad Request` for malformed syntax that the server couldn't parse. Use `422 Unprocessable Entity` when the syntax is mathematically correct, but the underlying data fails semantic business validation rules.
Does the HTTP Status Code Reference work offline?
Yes, the HTTP Status Code Reference is fully functional offline. Because this tool runs entirely in your browser, no data is ever uploaded to external servers. Once the page is loaded, you can seamlessly continue using it without an active internet connection. You can also install Knicknaks as a Progressive Web App (PWA) for native-like offline access.