Using the Google AMP Cache
The Google AMP Cache stores valid AMPs and provides a consistently fast access to AMPs. It is available for anyone to use.
AMP Cache URL Format
When possible, the Google AMP Cache will create a subdomain for each AMP document's domain by first converting it from IDN (punycode) to UTF-8. The caches replaces every
- (dash) with
-- (2 dashes) and replace every
. (dot) with
- (dash). For example,
pub.com will map to
Here is AMP Cache URL for
The converted AMP Cache URL consists of the following parts:
amp-dev: the publisher domain converted into a subdomain using the algorithm described above.
cdn.ampproject.org: the AMP Cache domain.
c: to indicate that it's an AMP document (there is also
ifor image and
rfor resources such as fonts).
s: indicating that the AMP Cache fetches the content from the origin using TLS (secure HTTPS).
amp.dev/examples/components/amp-img: the original URL excluding the scheme.
It is OK for URLs to include parameters in the query string, simply include these in the AMP Cache URL as well.
The AMP Cache uses a one-behind caching model which can be controlled by the
max-age cache directive. You can test the behavior with this sample page, which will prints the current date at serving time:
Redirect & Error Handling
Here are some examples for how the AMP Cache handles redirects and errors:
The AMP Cache follows redirects when resolving AMP URLs. For example, if an URL redirects to another AMP URL:
$ curl -I https://ampbyexample.com/components/amp-img/ HTTP/1.1 301 Moved Permanently Content-Type: text/html; charset=utf-8 Location: https://amp.dev/documentation/examples/components/amp-img/ ...
Then the AMP Cache will return the content of the resolved redirect for the original URL.
When a page is not found in the AMP Cache, it will show an error page and return a 404 status.
When a page is invalid AMP, the AMP Cache will return a 404 status.
If an URL returns a 5XX server errors, the AMP Cache will return a 404 status.
Written by @kul3r4