Retry-After
The Retry-After
response HTTP header indicates how long
the user agent should wait before making a follow-up request. There are three main cases
this header is used:
-
When sent with a
503
(Service Unavailable) response, this indicates how long the service is expected to be unavailable. -
When sent with a
429
(Too Many Requests) response, this indicates how long to wait before making a new request. -
When sent with 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 |
---|---|
Forbidden header name | no |
Syntax
http
Retry-After: <http-date>
Retry-After: <delay-seconds>
Directives
- <http-date>
-
A date after which to retry. See the
Date
header 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
(Service Unavailable) 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 |
---|
HTTP Semantics # field.retry-after |
Browser compatibility
BCD tables only load in the browser
See also
- Google Webmaster blog: How to deal with planned site downtime
503
(Service Unavailable)301
(Moved Permanently)