428 Precondition Required

The HTTP 428 Precondition Required response status code indicates that the server requires the request to be conditional.

Typically, this means that a required precondition header, such as If-Match, is missing.

When a precondition header is not matching the server side state, the response should be 412 Precondition Failed.

428 Precondition Required

• HTTP conditional requests
• If-Match
• 412