Complete reference guide for all HTTP status codes (1xx, 2xx, 3xx, 4xx, 5xx). Search, filter, and understand every response code with explanations, common causes, and solutions.
HTTP status codes are three-digit numbers returned by a server in response to a client's request. They indicate whether the request was successful, redirected, encountered an error, or requires further action. Understanding these codes is essential for web developers, system administrators, and anyone working with web APIs. Status codes are grouped into five classes: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error).
HTTP status codes are standardized three-digit numbers that a web server returns in response to an HTTP request from a client (usually a web browser or API client). They tell the client whether the request was successful, if it was redirected, or if an error occurred. The first digit of the status code defines the class of response.
4xx status codes indicate client errors — problems with the request itself, such as a missing page (404), insufficient permissions (403), or invalid syntax (400). 5xx status codes indicate server errors — problems on the server side, such as an internal server error (500), a bad gateway (502), or service unavailable (503). In short: 4xx means "you made a mistake," and 5xx means "the server made a mistake."
The most commonly encountered HTTP status code is 200 OK, which means the request was successful and the server returned the requested resource. However, the most famous (or infamous) status code is likely 404 Not Found, which appears when a requested page or resource cannot be found on the server.
Generally, no. 5xx errors are server-side problems, meaning the issue lies with the website's server, not your device or connection. As a visitor, you can try refreshing the page, clearing your browser cache, or waiting a few minutes. If the problem persists, it's up to the website's administrators to fix the underlying server issue.