// reference

HTTP Status Codes

Every common HTTP status code from 1xx to 5xx, with its name and what it means — grouped by category.

HTTP status codes report the outcome of a request in three digits. This reference groups the ones you actually see — informational, success, redirects, client errors and server errors — each with a short, plain-English explanation.

1xx — Informational

Code	Name	Meaning
`100`	Continue	Headers received; the client should send the request body.
`101`	Switching Protocols	The server is switching protocols as the client asked (e.g. to WebSocket).
`103`	Early Hints	Preload hints sent before the final response.

2xx — Success

Code	Name	Meaning
`200`	OK	Standard response for a successful request.
`201`	Created	The request succeeded and a new resource was created.
`202`	Accepted	The request was accepted but processing isn't complete.
`204`	No Content	Success, with no response body to return.
`206`	Partial Content	Part of the resource is returned (range request).

3xx — Redirection

Code	Name	Meaning
`301`	Moved Permanently	The resource has permanently moved to a new URL.
`302`	Found	The resource is temporarily at a different URL.
`303`	See Other	Fetch the resource with a GET at another URL.
`304`	Not Modified	The cached copy is still valid; no body is sent.
`307`	Temporary Redirect	Temporary redirect that preserves the HTTP method.
`308`	Permanent Redirect	Permanent redirect that preserves the HTTP method.

4xx — Client error

Code	Name	Meaning
`400`	Bad Request	The server can't process a malformed request.
`401`	Unauthorized	Authentication is required or has failed.
`403`	Forbidden	Authenticated, but not allowed to access this resource.
`404`	Not Found	The resource doesn't exist.
`405`	Method Not Allowed	The HTTP method isn't supported for this resource.
`406`	Not Acceptable	Can't produce a response matching the Accept headers.
`408`	Request Timeout	The client took too long to send the request.
`409`	Conflict	The request conflicts with the current state of the resource.
`410`	Gone	The resource has been permanently removed.
`415`	Unsupported Media Type	The request body format isn't supported.
`422`	Unprocessable Entity	Well-formed but semantically invalid (validation failed).
`429`	Too Many Requests	The client has sent too many requests (rate limited).

5xx — Server error

Code	Name	Meaning
`500`	Internal Server Error	A generic server-side failure.
`501`	Not Implemented	The server doesn't support the requested functionality.
`502`	Bad Gateway	An upstream server returned an invalid response.
`503`	Service Unavailable	The server is temporarily overloaded or down.
`504`	Gateway Timeout	An upstream server didn't respond in time.
`505`	HTTP Version Not Supported	The HTTP version isn't supported.

// quick guide

Commonly confused, explained

Redirects: 301, 302, 303, 307 or 308?

Two questions decide it. Is the move permanent (301, 308) or temporary (302, 303, 307)? And must the request method stay the same? 307 and 308 keep the method and body, while 301 and 302 let some clients turn POST into GET. 303 explicitly asks for a GET, which suits the Post/Redirect/Get pattern.

301 Moved Permanently 308 Permanent Redirect 302 Found 307 Temporary Redirect 303 See Other

401 or 403?

401 means the server does not know who you are: send valid credentials. 403 means it knows who you are and the answer is still no, so authenticating again will not help. Some APIs return 404 instead of 403 to avoid revealing that a resource exists.

401 Unauthorized 403 Forbidden 404 Not Found

Server errors: 500, 502, 503 or 504?

500 is an unexpected failure in the application. 502 means a gateway got an invalid response from the server behind it, 503 means the service says it cannot take requests right now (often with Retry-After), and 504 means the upstream did not answer in time. The code tells you which layer to investigate first.

500 Internal Server Error 502 Bad Gateway 503 Service Unavailable 504 Gateway Timeout

Success codes for APIs: 200, 201, 202 or 204?

Use 200 when the response carries a result, 201 when a request created a new resource (with a Location header), 202 when work was accepted but is not finished, and 204 when it succeeded and there is nothing to return.

200 OK 201 Created 202 Accepted 204 No Content

Bad request, validation or rate limit: 400, 422, 429?

400 means the request could not be understood. 422 means it was well-formed but failed validation. 429 means this client sent too many requests and should wait for Retry-After.

400 Bad Request 422 Unprocessable Entity 429 Too Many Requests 415 Unsupported Media Type

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Aug 28, 2026 · 2 min read Anatomy of an HTTP Request and Response A line-by-line breakdown of an HTTP request and response — the request line, status line, headers, and body — so raw HTTP stops looking like noise. HTTP Headers Parser Aug 28, 2026 · 3 min read The Complete Guide to HTTP for Developers HTTP end to end — what it is, the anatomy of a request and response, methods, status codes, and headers — with links to focused deep-dives and tools. HTTP Status Code Lookup Aug 11, 2026 · 1 min read How to Read and Parse HTTP Headers The anatomy of HTTP request and response headers, how to turn raw headers into JSON, and why duplicates become arrays. HTTP Headers Parser Aug 11, 2026 · 2 min read HTTP Status Codes Explained (1xx–5xx) What HTTP status code classes mean, the codes you'll actually hit, and how to tell a client error from a server error. HTTP Status Code Lookup

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Last updated: Oct 2, 2026