Retry-After header
The HTTP Retry-After response header indicates how long the user agent should wait before making a follow-up request.
There are three main cases this header is used:
- In a
503 Service Unavailableresponse, this indicates how long the service is expected to be unavailable. - In a
429 Too Many Requestsresponse, this indicates how long to wait before making a new request. - In a redirect response, such as
301 Moved Permanently, this indicates the minimum time that the user agent is asked to wait before issuing the redirected request.
| Header type | Response header |
|---|
Syntax
http
Retry-After: <http-date>
Retry-After: <delay-seconds>
Directives
<http-date>-
A date after which to retry. See the
Dateheader for more details on the HTTP date format. <delay-seconds>-
A non-negative decimal integer indicating the seconds to delay after the response is received.
Examples
Dealing with scheduled downtime
Support for the Retry-After header on both clients and servers is still
inconsistent. However, some crawlers and spiders, like the Googlebot, honor the
Retry-After header. It is useful to send it along with a 503 response, so that search engines will keep
indexing your site when the downtime is over.
http
Retry-After: Wed, 21 Oct 2015 07:28:00 GMT
Retry-After: 120
Specifications
| Specification |
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| HTTP Semantics # field.retry-after |
Browser compatibility
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- No support
- No support
- See implementation notes.
See also
503 Service Unavailable301 Moved Permanently- How to deal with planned site downtime on developers.google.com (2011)