503 Service Unavailable

503 Service Unavailable is a status that a server can send when it is overloaded, or otherwise incapable of handling a request. Maybe the server is just booting up, or perhaps the application is partially down.

When this status is returned, a server can optionally include a Retry-After header to tell a client when to try the request again.


HTTP/1.1 503 Service Unavailable
Content-Type text/plain
Retry-After: 1800

System overload! Give us some time to increase capacity.


HTTP series

This article is part of a series about the HTTP protocol. Read them all here:

Informational 1xx

Successful 2xx

Redirection 3xx

Client Error 4xx

Server Error 5xx

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