Signed Exchanges: Branded AMP URLs have arrived

Google’s AMP cache now displaying original domain URLs instead of the ‘’ prefix

Google has been steadily working to enable Signed Exchanges, which enables cached AMP URLs to feature the original domain names – anywhere an AMP page is displayed. The technology is now available in a developer preview in version 71 of Chrome, allowing publishers, businesses and retailers to try it out before it goes into full production.

As covered in an earlier post, Signed Exchanges are part of a wider initiative called Web Packaging, which is an ongoing effort that includes feedback from key stakeholders, including  standards bodies, browser vendors, security experts and web developers.

So long to ‘’ and hello branded domain

This represents a benchmark in the evolution of the open-source AMP initiative by both maintaining the unprecedented load speeds of pre-cached, pre-rendered mobile pages, and the attribution, branding and ownership associated with the origin URL.

Signed Exchanges have benefits that extend the branded URL bar, including:

  • Using cryptographic signatures, guarantees that content is exactly what retailer intends to display;
  • Enables the browser to treat a document as belonging to the retailer’s origin, which paves the way for greater insight and performance, allowing businesses to use first-party cookies to customize content, execute service workers and measure analytics; and
  • Protection of a website’s brand at the onset of discovery on acquisition channels – delivering a totally seamless experience from AMP-enabled landing pages and into the canonical mobile site.

How does Signed Exchanges/ Web Packaging work?

To get a better idea for how the new technology works, let’s look under the hood at three areas: 1. Prefetching, 2. Signed Exchanges,  and 3. AMP Packager.


Guaranteed fast page loads are powered by prefetching. When a search returns an AMP page, the SERP instructs the browser to fetch and partially load the AMP document in the background. As a result, when a user taps an AMP listing, the AMP document can be displayed instantly.

According to Google: An important privacy principle is that third parties shouldn’t be able to determine that the user is interested prior to engagement (i.e. entering the site). If preload caused a browser to make network requests to servers other than Google’s, then some of the user’s intent and their queries would leak to sites the user never intended to click on. To protect the user’s privacy, neither the document nor resources fetched before loading the document, can be fetched from third parties. And this is why Google Search loads the document from a Google server – or the AMP Cache. Only when users signal intent to load the document do those resources get fetched. This mechanism is called “Privacy Preserving Prefetching” and it creates a buffer between the user and the business.

Signed Exchanges

To achieve the best of both worlds – protecting a user’s privacy, while maintaining the original URL domain – Signed Exchanges were developed over the course of 2018 in close partnership with standards bodies.

As Google describes, Signed Exchanges provide digital proof to a browser that the document delivered by an AMP Cache has not been modified from what the publisher or business intended. When a browser sees a Signed Exchange and can validate the signature, the browser can display the original URL, regardless of where the file was delivered from.

AMP Packager

To build Signed Exchanges, the AMP team built a tool to package and serve original domains. The tool is called the AMP Packager, which WompMobile has already started working with and is exploring the Signed Exchanges feature with clients.

AMP Packager runs on a businesses’ own infrastructure as a web-server backend. Like a proxy, it accepts an HTTP request for an AMP Web Package, forwarding the request to the backend – transforming it into a Signed Exchange. And just like that, your branded domain is displayed in search.

We’d love to work with you

Powering more than 15 million AMP pages – for clients ranging from retail, healthcare and publishing – we’re excited about this news. It’s another signal of the staying power of the AMP Project and the importance of improving experiences across the mobile web.

With Signed Exchanges, websites can have it all – attribution, branding and ownership of the content, while ensuring instantaneous page loads. If you’d like to explore AMP and Signed Exchanges, we’d love to hear from you. To learn more, reach out to one of our mobile experts for a free consultation.