HTTP Status Codes

Continue

Request headers received; the client should continue sending the body

Switching Protocols

The server is switching protocols at the client's request (e.g. WebSocket upgrade)

Processing

The server received the request and is processing it, but has no response yet (WebDAV)

Early Hints

Early hints; a Link header may be sent before the final response

OK

Request succeeded; the body contains the result

Created

Resource created, usually with a Location header

Accepted

Request accepted but not yet processed (async task)

Non-Authoritative Information

Metadata comes from a third-party copy, not authoritative from the origin

No Content

Succeeded with no response body (often used for DELETE / PUT)

Reset Content

Asks the client to reset the form view (rare)

Partial Content

Partial content returned (resumable downloads, video seeking)

Multi-Status

Multi-status response (WebDAV)

Moved Permanently

Resource moved permanently; update your bookmarks

⚠ SEO ranking is passed along

Found

Temporary redirect

⚠ Most cases should use 303 or 307 instead

See Other

Fetch another address with GET

⚠ Use it for post-POST redirects instead of 302

Not Modified

Cache is still valid; no need to retransmit

Temporary Redirect

Temporary redirect that preserves the original method

Permanent Redirect

Permanent redirect that preserves the original method

Bad Request

Malformed request syntax or invalid parameters

Unauthorized

Not authenticated (missing or invalid credentials)

⚠ Strictly this means "unauthenticated", not "no permission"

Payment Required

Reserved status code, now mostly used for paywalls

Forbidden

Authenticated but not allowed to access

Not Found

Resource does not exist

Method Not Allowed

This resource does not support the HTTP method

Not Acceptable

Cannot produce content matching the Accept header

Proxy Authentication Required

Must authenticate with the proxy first

Request Timeout

The client did not finish the request within the server's wait time

Conflict

Conflicts with the current resource state (e.g. concurrent writes)

Gone

The resource existed but has been permanently deleted

Length Required

Missing Content-Length header

Precondition Failed

A conditional request (If-Match etc.) was not satisfied

Payload Too Large

Request body exceeds the server limit

URI Too Long

The requested URI is too long

Unsupported Media Type

Request body format is not supported

Range Not Satisfiable

The requested range cannot be satisfied (common in resumable downloads)

Expectation Failed

Cannot satisfy the Expect header

I'm a teapot

April Fools' RFC 2324; often appears in easter eggs and tests

⚠ Not a standard status code

Misdirected Request

The request was routed to a server that cannot respond (HTTP/2 connection reuse)

Unprocessable Entity

Syntax is fine but semantic validation failed (commonly form validation)

Locked

Resource is locked (WebDAV)

Too Early

The server declines requests that might be replayed (TLS early data)

Upgrade Required

The client must upgrade its protocol

Precondition Required

Requires a conditional request to avoid concurrent overwrites

Too Many Requests

Rate limited; see the Retry-After header

Request Header Fields Too Large

Request headers too large (often an oversized Cookie)

Unavailable For Legal Reasons

Unavailable for legal reasons

Internal Server Error

Internal server error

Not Implemented

The server does not support this functionality

Bad Gateway

The gateway received an invalid response from upstream

Service Unavailable

Service temporarily unavailable (overload or maintenance)

Gateway Timeout

The gateway timed out waiting for upstream

HTTP Version Not Supported

The HTTP version used by the request is not supported

Insufficient Storage

Insufficient storage (WebDAV)

Network Authentication Required

Network authentication required (public WiFi portal)