🌐HTTP Status Codes
A fast, searchable reference for every HTTP status code — grouped by class, with plain-English descriptions and usage notes.
Free HTTP Status Codes Reference
Not sure what a status code means — or which one to return? Our free HTTP status codes reference covers every standard code from 100 to 511, plus common extensions like 429 Too Many Requests and 451 Unavailable For Legal Reasons, all in one searchable page. Type a number or keyword to jump straight to the code you're looking for, or browse by class: informational, success, redirection, client error, or server error.
Every entry includes a plain-English description and a concise note on when you'd actually encounter it — in an API response, a browser redirect, a rate-limiter, or a server failure. One-click copy grabs the code or the full status string, and stable URL fragments let you link directly to any code for documentation or team discussions.
Everything is bundled locally — no server calls, no tracking. Simply search or browse to find the status code you need, instantly.
About the HTTP Status Codes Reference
Features
Complete dataset
Every 1xx-5xx status code, bundled locally at build time — no runtime fetch.
Instant search
Search by code number or by keyword in the name, description, or usage note.
Class filters
Filter to just 1xx, 2xx, 3xx, 4xx, or 5xx, combinable with the search box.
Color and label coded
Each class has a distinct colour badge plus a text label, never colour alone.
Deep links and copy
Every code has a stable URL fragment and one-click copy for the code or full string.
Fully client-side
All data is static and bundled — nothing is fetched or transmitted.
The five status code classes
HTTP status codes are grouped into five classes by their first digit: 1xx informational responses, 2xx successful responses, 3xx redirection messages, 4xx client errors, and 5xx server errors. Knowing which class a code belongs to is often enough to understand the general shape of the problem before reading the specific code.
Frequently Asked Questions
What are HTTP status codes?
Three-digit codes returned by a server with every HTTP response, indicating whether the request succeeded, failed, or requires further action.
What do the five classes mean?
1xx is informational (request received), 2xx is success, 3xx is redirection, 4xx is a client-side error, and 5xx is a server-side error.
How do I look up a specific code?
Type the number or a keyword into the search box and the matching code appears immediately; you can also filter by class using the tab buttons.
Can I link directly to a code?
Yes — every code has a stable URL fragment (e.g. /dev/http-status-codes#404) you can bookmark or share.
Does it include unofficial codes like 418?
Yes. Widely-used unofficial and extended codes (418, and others) are included and marked with a badge.
Which specification does this follow?
The primary reference is RFC 9110 (HTTP Semantics), with additional codes from WebDAV (RFC 4918) and common unofficial extensions.
What's the difference between 301 and 302?
301 is a permanent redirect (clients and search engines should update the URL); 302 is temporary (the original URL remains canonical).
When should an API return 400 vs 422?
400 (Bad Request) covers malformed syntax; 422 (Unprocessable Content) means the syntax is valid but the server can't process the semantics — common in REST APIs for validation errors.
Is any data sent to a server?
No. All status code data is bundled into the page; nothing is fetched at runtime and nothing you type is transmitted anywhere.
Does it work on mobile?
Yes, fully responsive; the search, filters, and code list fit any screen without overflow.