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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 compatibilityUpdate compatibility data on GitHub

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

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
503 Yes 12 Yes Yes Yes Yes
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
503 Yes Yes Yes Yes Yes Yes

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/503