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

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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes Yes Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes Yes Yes Yes Yes

See also

Document Tags and Contributors

 Contributors to this page: RayannTedds, haroldfredshort, fscholz
 Last updated by: RayannTedds,