HTTP Status Codes Reference

Searchable reference of all common HTTP status codes with descriptions, use cases, and color-coded categories.

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. They are grouped into five categories: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error). Understanding these codes is essential for debugging APIs, monitoring web applications, and handling errors correctly in your code.

This reference tool provides a complete, searchable list of HTTP status codes with their meanings, descriptions, and common use cases — all on a single page for quick lookup.

How to Use This HTTP Status Code Reference

Browse by category — Scroll through status codes organized by their category (1xx, 2xx, 3xx, 4xx, 5xx).

Search for a code — Type a status code number or keyword to quickly find the one you're looking for.

Read the description — Each code includes its official name and a clear explanation of when and why it is used.

Common Use Cases

API debugging — Look up status codes returned by APIs to understand error responses and fix integration issues.

Error handling — Reference the correct status codes when implementing error responses in your backend services.

SEO troubleshooting — Understand redirect codes (301, 302, 307) and client errors (404, 410) that affect search engine indexing.

Learning web development — Study HTTP status codes as part of understanding how the web and REST APIs work.

Frequently Asked Questions

What are HTTP status codes?

HTTP status codes are three-digit numbers returned by a web server in response to a request. They indicate whether the request was successful (2xx), redirected (3xx), caused a client error (4xx), or a server error (5xx).

What is the difference between 401 and 403?

A 401 Unauthorized means the request lacks valid authentication credentials — the user needs to log in. A 403 Forbidden means the server understood the request but the authenticated user does not have permission to access the resource.

What does a 500 Internal Server Error mean?

A 500 status code indicates an unexpected server-side error. It means the server encountered a condition it could not handle. Common causes include unhandled exceptions, misconfigured servers, or database connection failures.

What is a 301 redirect vs a 302 redirect?

A 301 is a permanent redirect — search engines transfer SEO value to the new URL. A 302 is a temporary redirect — the original URL retains its SEO value. Use 301 for permanent URL changes and 302 for temporary moves.