OneTaskBy Tim King · Updated
HTTP Status Codes List
List of HTTP Response Codes From 100 Continue to 511, With Defining RFCs
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How the HTTP Status Codes works
This HTTP status codes list is the official IANA registry: every code a standard has defined, from 100 Continue to 511 Network Authentication Required. Each row gives the reason phrase, the class the code belongs to and the RFC that defines it. Search by number or word, or download the table.
How to read the HTTP status codes list
The first digit sets the class. 1xx codes are informational and rarely seen outside protocol code. 2xx means the request worked, 3xx asks the client to go somewhere else, 4xx means the client sent something wrong, and 5xx means the server failed. A client that meets an unknown code is required to treat it like the x00 code of its class, which is why new codes can be added safely.
What the reference column means
Most codes now point to RFC 9110, the 2022 document that restated HTTP semantics and replaced the older RFC 7231 family. Codes added later, or for one extension such as WebDAV, point to their own RFC. Unassigned ranges from the registry are left out, so every row is a code that software might send.
Codes you will not find here
Some popular numbers are not registered. 418 I'm a teapot came from an April Fools RFC and is reserved rather than assigned; Nginx's 499 and Cloudflare's 52x codes are vendor inventions that appear in logs but not in the standard. For a plain-English explanation of what a code means and how to fix it, use the lookup tool linked below.
FAQ
How many HTTP status codes are there?
The registry holds a little over sixty assigned codes, spread across the five classes, and the 4xx class is the largest. Only about a dozen appear regularly in web traffic: 200, 201, 204, 301, 302, 304, 400, 401, 403, 404, 429, 500, 502 and 503 cover almost every real response.
What is the difference between 401 and 403?
401 Unauthorized means the request has no valid credentials and should be retried after logging in. 403 Forbidden means the server knows who you are and still refuses. The naming is confusing because 401 really means unauthenticated, but the codes have kept those names since the first HTTP specification.
Can I use this list in my own project?
Yes. IANA places its protocol registries in the public domain, so you can ship the CSV or JSON inside an application, a linter or documentation without restriction. The citation line under the table records where and when the list was retrieved.
See also: all Tech Data tools, Everyday Data.
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