428
Precondition Required
Client errors (4xx)·RFC 6585
What 428 means
The server requires the request to be conditional to avoid lost updates.
Prompts clients to send If-Match so two simultaneous updates do not silently overwrite each other.
Client errors (4xx)
The request contains an error from the client — bad syntax, missing auth or a wrong URL.
Other 4xx codes
400Bad Request401Unauthorized402Payment Required403Forbidden404Not Found405Method Not Allowed406Not Acceptable407Proxy Authentication Required408Request Timeout409Conflict410Gone411Length Required412Precondition Failed413Content Too Large414URI Too Long415Unsupported Media Type416Range Not Satisfiable417Expectation Failed418I'm a teapot421Misdirected Request422Unprocessable Content423Locked424Failed Dependency425Too Early426Upgrade Required429Too Many Requests431Request Header Fields Too Large451Unavailable For Legal Reasons
FAQ — 428
What does HTTP 428 mean?
428 Precondition Required: The server requires the request to be conditional to avoid lost updates. Prompts clients to send If-Match so two simultaneous updates do not silently overwrite each other.
Which class does status code 428 belong to?
428 is a Client errors (4xx) code. The request contains an error from the client — bad syntax, missing auth or a wrong URL.
Where is the 428 code defined?
Status code 428 is defined in RFC 6585 and is part of the IANA HTTP Status Code Registry.