HTTP Status Codes Reference
Quick reference for HTTP status codes and their meanings.
What Are HTTP Status Codes?
HTTP status codes are three-digit numbers returned by a web server in response to a client's request. They indicate whether the request was successful, redirected, resulted in an error, or requires further action. Status codes are defined in RFC 7231 and are a fundamental part of the HTTP protocol that powers the web.
Status Code Categories
| Range | Category | Meaning |
|---|---|---|
| 1xx | Informational | Request received, continuing process |
| 2xx | Success | Request successfully received, understood, and accepted |
| 3xx | Redirection | Further action needed to complete the request |
| 4xx | Client Error | Request contains bad syntax or cannot be fulfilled |
| 5xx | Server Error | Server failed to fulfill a valid request |
Most Common Status Codes
- 200 OK: The standard success response for GET requests.
- 201 Created: A new resource was successfully created (POST/PUT).
- 301 Moved Permanently: The resource has been permanently moved to a new URL. Search engines transfer SEO value.
- 302 Found: Temporary redirect — the resource is temporarily at a different URL.
- 400 Bad Request: The server cannot process the request due to client-side errors (malformed syntax, invalid parameters).
- 401 Unauthorized: Authentication is required but was not provided or is invalid.
- 403 Forbidden: The server understands the request but refuses to authorize it.
- 404 Not Found: The requested resource does not exist on the server.
- 429 Too Many Requests: Rate limiting — the client has sent too many requests.
- 500 Internal Server Error: A generic server-side error occurred.
- 502 Bad Gateway: A reverse proxy or gateway received an invalid response from the upstream server.
- 503 Service Unavailable: The server is temporarily down (maintenance, overload).
How to Use This Tool
- Browse the complete list of HTTP status codes organized by category.
- Click any status code to see its detailed description.
- Use the search bar to quickly find a specific status code.
- Reference the descriptions when building or debugging APIs.
Why Use This Tool?
- Complete reference guide for all HTTP status codes (1xx–5xx).
- Includes detailed descriptions and common use cases.
- Searchable and categorized for quick access.
- Essential reference for API developers and web engineers.
Frequently Asked Questions
What is the difference between 401 and 403?
401 Unauthorized means "you are not authenticated" — provide valid credentials and retry. 403 Forbidden means "you are authenticated but do not have permission" — re-authenticating will not help.
When should I use 301 vs 302 redirects?
Use 301 for permanent moves (domain changes, URL restructuring) — search engines will update their index. Use 302 for temporary redirects (maintenance pages, A/B tests) — search engines keep the original URL.