503 Service Unavailable

The HyperText Transfer Protocol (HTTP) 503 Service Unavailable server error response code indicates that the server is not ready to handle the request.

Common causes are a server that is down for maintenance or that is overloaded. This response should be used for temporary conditions and the Retry-After HTTP header should, if possible, contain the estimated time for the recovery of the service.

Note: together with this response, a user-friendly page explaining the problem should be sent.

Caching-related headers that are sent along with this response should be taken care of, as a 503 status is often a temporary condition and responses shouldn't usually be cached.

Status

503 Service Unavailable

Specifications

Specification Title
RFC 7231, section 6.6.4: 503 Service Unavailable Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

Browser compatibility

BCD tables only load in the browser

The information shown below has been pulled from MDN's GitHub (https://github.com/mdn/browser-compat-data).

See also