What Is an HTTP Status Codes Reference?
This HTTP status codes reference provides a complete guide to all standard HTTP response codes. Status codes are three-digit numbers returned by web servers to indicate the result of a client’s request, essential for web development and API debugging.
How to Use This HTTP Status Codes Tool
- Browse or search for a specific status code.
- View the code category, name, and detailed description.
- Learn when each status code is used and how to handle it.
Key Concepts
HTTP status codes are grouped into five classes: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error). Common codes include 200 (OK), 301 (Moved Permanently), 404 (Not Found), and 500 (Internal Server Error). Understanding these codes is critical for debugging API integrations, handling errors gracefully, and implementing proper redirect logic.
Frequently Asked Questions
What is the difference between 301 and 302 redirects?
A 301 indicates a permanent redirect—browsers and search engines update their records. A 302 is temporary, meaning the original URL should still be used for future requests.
When should I use 400 vs 422?
Use 400 (Bad Request) for malformed syntax the server cannot parse. Use 422 (Unprocessable Entity) when the syntax is valid but the content is semantically incorrect.
What does a 503 status code mean?
503 (Service Unavailable) means the server is temporarily unable to handle requests, usually due to maintenance or overload. It signals a temporary condition with a Retry-After header.