HTTP 428 Precondition Required

What is HTTP 428 Precondition Required?

The 428 (Precondition Required) status code indicates that the origin server requires the request to be conditional. This helps prevent the "lost update" problem where a client overwrites another client's changes without being aware of them. Clients should include a precondition header like If-Match or If-Unmodified-Since.

Common Use Cases

• Preventing lost updates in collaborative editing
• Ensuring atomic operations on shared resources

// Laravel - requiring If-Match header
if (! $request->header('If-Match')) {
    return response()->json([
        'error' => 'Precondition required',
        'message' => 'Include If-Match header with current resource ETag',
    ], 428);
}