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HTTP Status Code Reference

Searchable reference of all HTTP status codes with descriptions. Quickly look up what any status code means.

What are HTTP Status Codes?

HTTP status codes are three-digit numbers returned by web servers to indicate the result of a client’s request. Every time your browser, API client, or application makes an HTTP request, the server responds with a status code that tells you whether the request succeeded, failed, or requires further action.

Understanding these codes is essential for web development, API integration, and debugging. Our comprehensive reference covers all standard HTTP status codes with clear explanations, organized by category for quick lookup.

How to Use This Reference

  1. Browse by category — codes are grouped into 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error)
  2. Search for a specific code to find its meaning and when it’s used
  3. Use the descriptions to understand what went wrong when debugging API calls
  4. Bookmark this page for quick reference during development

Common Use Cases

  • API debugging — Understand why an API call returned 401 vs 403 vs 404
  • Web server configuration — Set up proper redirects (301 vs 302) for SEO
  • Error handling — Implement correct error responses in your backend API
  • Monitoring and alerting — Know which status codes indicate problems worth alerting on
  • SEO optimization — Ensure proper use of 301 redirects and avoid soft 404s

Frequently Asked Questions

What’s the difference between 401 and 403?

401 Unauthorized means the request lacks valid authentication credentials — the user needs to log in. 403 Forbidden means the server understood the request and the user is authenticated, but they don’t have permission to access the resource.

When should I use 301 vs 302 redirects?

Use 301 (Moved Permanently) when a page has permanently moved to a new URL — search engines transfer SEO value to the new URL. Use 302 (Found) for temporary redirects where the original URL will be used again in the future.

What does a 500 error mean?

500 Internal Server Error is a generic server-side error. It means something went wrong on the server but it couldn’t be more specific. Check your server logs for the actual error — common causes include unhandled exceptions, database connection failures, or misconfigured server settings.

  • JSON Formatter — Format API JSON responses for debugging
  • JWT Decoder — Decode authentication tokens when debugging 401 errors
  • IP Lookup — Look up IP addresses when debugging connection issues