503
Service Unavailable
Server ErrorThe server is not ready to handle the request, often due to overload or maintenance.
Category: 5xx Server Errors Standard: RFC 9110 First Appeared: HTTP/1.0
What is 503 Service Unavailable?
HTTP 503 Service Unavailable means the server is temporarily unable to handle the request, usually because it is overloaded or down for maintenance. It is expected to be temporary.
Client Request
Server
Server Error
Common Causes
Server overloaded by traffic spikes
Planned maintenance window
A backend or dependency is temporarily unavailable
Autoscaling has not caught up with demand
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