The server is temporarily unable to handle the request, usually due to maintenance or overload.
return new Response('Service temporarily unavailable', {
status: 503,
headers: { 'Retry-After': '60' },
});Tell clients when to retry. Helps prevent retry storms.
ObserveOne monitors service availability and triggers alerts the moment a 503 is detected.
Start Monitoring FreeThe client has sent too many requests in a given time period. The server is rate-limiting to protect itself.
The server encountered an unexpected condition that prevented it from fulfilling the request.
The server cannot process the request due to malformed syntax, invalid parameters, or bad encoding.
The request requires authentication. The client must provide valid credentials.
The server understood the request but refuses to authorize it. Authentication won't help — the user lacks permissions.