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).
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
503 | Chrome Full support Yes | Edge Full support 12 | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support