In the coming weeks, Google will be launching Signed Exchanges in Google Search for desktop users. This primarily impacts sites that utilities dynamic serving with the vary user-agent header but should not impact sites using responsive web design or separate mobile and desktop URLs.
The announcement. This announcement was posted in the Google Groups by Devin Mullins of Google. Devin Mullins wrote:
Google Search is planning to launch SXG support for desktop users in the coming weeks.
Sites using responsive web design or separate mobile/desktop URLs don’t need to take action.
Sites using dynamic serving (varying by User-Agent header) will need to annotate their pages as mobile- or desktop-only, as documented here. For example:
Otherwise, desktop users may see the mobile version of the page.
We’re reaching out individually to SXG sites who we’ve found to use dynamic serving, but I wanted a broad announcement in case there are any that we miss.
More technical details. For almost all sites, since most sites do not use dynamic serving, no action is needed. Sites serving different HTML based on the user-agent header will need to opt out by adding a meta tag to your page. The meta tag is:
For more details on the meta tags, see this help document.
What are signed exchanges. Google defines them as “Signed HTTP Exchange (or “SXG”) is a subset of the emerging technology called Web Packages, which enables publishers to safely make their content portable, i.e. available for redistribution by other parties, while still keeping the content’s integrity and attribution. Portable content has many benefits, from enabling faster content delivery to facilitating content sharing between users, and simpler offline experiences.”
This is a solution Google came up with when publishers wanted to use their real URLs to serve AMP.
Why we care. If you are using dynamic serving and want to use signed exchanges, there is nothing for you to do. If you are using dynamic serving and do not want to use signed exchanges, you can opt out with the meta tag. If you are using another set up, Google says there is nothing changing and nothing for you to do.
Google also said it will communicate to those who will be impacted by this what is happening. So keep an eye out on your inbox and/or your Google Search Console notices for any messaging about signed exchanges for desktop.