HTTP Status Code Checker
Look up any HTTP status code with detailed explanations, categories, and usage examples.
About HTTP Status Code Checker
An HTTP status code checker provides detailed information about any HTTP status code, including its category, meaning, common causes, and usage examples. HTTP status codes are three-digit numbers returned by web servers in response to HTTP requests. They are organized into five categories: informational (1xx), success (2xx), redirection (3xx), client errors (4xx), and server errors (5xx). Understanding these codes is essential for web development, API design, debugging, and system administration.
How to Use
Enter an HTTP status code (100-599) or browse the categorized list. The checker displays the code name, category, description, common scenarios that trigger it, and recommended actions for both client and server side. You can browse all codes by category or search for specific codes.
Formula / Key Equations
Status code categories: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), 5xx (Server Error). Common codes: 200 (OK), 201 (Created), 301 (Moved Permanently), 304 (Not Modified), 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404 (Not Found), 500 (Internal Server Error), 502 (Bad Gateway), 503 (Service Unavailable).
Common Use Cases
Debugging web application errors and unexpected responses. Designing RESTful APIs with appropriate status codes. Understanding server error logs. Troubleshooting website access issues. Learning HTTP protocol for web development. Creating error handling logic in web applications.
Limitations
This tool provides reference information about HTTP status codes. It does not actually make HTTP requests to check a URL status — for that, use a dedicated HTTP request tool. Some codes have subtle differences between HTTP/1.1 and HTTP/2 specifications.
Frequently Asked Questions
What is the most common HTTP status code?
200 (OK) is by far the most common, indicating a successful request. The most common error is 404 (Not Found), followed by 500 (Internal Server Error), 403 (Forbidden), and 301 (Moved Permanently). Monitoring these codes helps identify website health issues.
What is the difference between 401, 403, and 404?
401 (Unauthorized) means authentication is required but not provided. 403 (Forbidden) means you are authenticated but not authorized to access the resource. 404 (Not Found) means the requested resource does not exist at the given URL.
When should I use 301 vs 302 redirect?
301 (Moved Permanently) tells browsers and search engines to update their records to the new URL and passes SEO link equity. 302 (Found/Temporary) redirects temporarily so search engines keep the original URL indexed. Use 301 for permanent URL changes and 302 for temporary redirects.
What does 502 Bad Gateway mean?
502 means the server acting as a gateway received an invalid response from an upstream server. Common causes include the backend server being down, misconfigured, or timing out. This is often seen with reverse proxies (nginx, Cloudflare) when the origin server is not responding.
What HTTP status code should my API return?
RESTful API conventions: 200 for successful GET/PUT, 201 for successful POST, 204 for successful DELETE, 400 for invalid input, 401 for missing auth, 403 for insufficient permissions, 404 for nonexistent resources, 409 for duplicates, 422 for validation errors, 500 for unexpected errors.