HTTP Status Code Reference
Complete reference for HTTP status codes. Search, filter by category, and click to see details.
1xx Informational
2xx Success
3xx Redirection
4xx Client Error
5xx Server Error
Complete Reference
All standard HTTP status codes from 1xx to 5xx, with names, descriptions, and real-world usage examples.
Search & Filter
Quickly find status codes by number, name, or description. Filter by category (1xx-5xx) with one click.
Detailed Explanations
Click any status code to expand and see a detailed explanation with common usage scenarios.
How to Use the HTTP Status Code Reference
- 1. Browse all HTTP status codes organized by category (1xx Informational, 2xx Success, etc.).
- 2. Use the search box to find a specific status code by number, name, or description.
- 3. Click the category filter buttons to show only codes from a specific range.
- 4. Click on any status code to expand and read the detailed explanation and usage scenarios.
Frequently Asked Questions
What are HTTP status codes?
HTTP status codes are three-digit numbers returned by a server in response to a client request. They indicate whether a request was successful, redirected, or resulted in an error. The first digit defines the class: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), 5xx (server error).
What is the difference between 401 and 403?
401 Unauthorized means the client has not authenticated itself — providing valid credentials may allow access. 403 Forbidden means the server understood the request but refuses to authorize it — even with valid credentials, access is denied due to insufficient permissions.
When should I use 404 vs 410?
404 Not Found means the resource was not found and may return in the future. 410 Gone means the resource has been intentionally and permanently removed. Use 410 to tell search engines to remove the URL from their index.
What causes a 502 Bad Gateway error?
A 502 error occurs when a server acting as a gateway or reverse proxy (like Nginx or a load balancer) receives an invalid response from the upstream application server. Common causes include the upstream server being down, crashing, or taking too long to respond.