HTTP Status Code Reference
Searchable reference for all HTTP status codes (1xx–5xx). Includes descriptions, common causes, and when to use each code.
Why use an HTTP Status Code Reference?
HTTP status codes are the standard way servers communicate the result of a request to clients. Knowing the difference between 401 and 403, or 301 and 302, prevents hours of debugging and avoids SEO mistakes. This searchable reference covers all standard codes with clear descriptions. Combine it with DNS lookup and port reference for a complete networking toolkit in the networking category.
Instant search
Search by status code number, name, or keyword — results filter in real time so you find the code you need in seconds.
Category filtering
Filter by category (2xx success, 4xx client error, etc.) to quickly narrow down to the relevant range of codes.
Developer explanations
Each code includes a practical description written for developers — not just the RFC spec wording.
HTTP status code categories
The five status code classes each represent a distinct category of server response. Understanding the class tells you immediately whether to look at the client, the server, or the network.
| Class | Category | Common codes | Meaning |
|---|---|---|---|
| 1xx | Informational | 100, 101 | Request received, processing is continuing |
| 2xx | Success | 200, 201, 204 | Request received, understood, and accepted |
| 3xx | Redirection | 301, 302, 304 | Further action needed — client must follow a redirect |
| 4xx | Client Error | 400, 401, 403, 404, 429 | The request has an error — the problem is on the client side |
| 5xx | Server Error | 500, 502, 503, 504 | Server failed — the problem is on the server side |