What’s more progressive than a progressive web app? A progressive web app with accelerated mobile pages technology.

The search giant in May announced that companies could now code these two technologies together to deliver a fast and experience-rich mobile site, such as a mobile site that can also send push notification and shoppers can scroll through a carousel of product images horizontally. Some retailers, such as seller of woods products Carved LLC, have tried it. Here’s how the technology works:

A progressive web app, or PWA, offers the look and customer engagement of an app, but in a mobile website. For example, PWAs allow retailers to send web push notifications to a shopper’s smartphone and typically load faster than traditional mobile websites. A PWA uses responsive design techniques to format the web page to the size of the screen the consumer is viewing it on.

Accelerated mobile pages, or AMP pages, allow a retailer to build lightweight mobile pages that load as fast as possible on smartphones when a consumer comes to the page via Google Search. The pages load super fast because the HTML code contains restrictions, such as not allowing custom Javascript coding. AMP also uses AMP Cache, which is Google’s content delivery network that validates that every page works and doesn’t depend on external resources, such as suggested products powered by an e-commerce technology vendor. Retailers can have related products on an AMP page, but it has to be coded in certain way to meet AMP specifications.

Now, online retailers can connect AMP pages via PWA.

For a retailer just with a progressive web app, every time a consumer visits that retailer’s site on a smartphone she visits the progressive web app site.

For a retailer just with AMP pages, a consumer only sees such pages when coming from Google smartphone search results. If she taps on a link on the AMP landing page, she is then redirected to the retailer’s mobile website.

For a retailer that has connected its AMP pages to its PWA, consumers can have a fast experience both from search and throughout the entire mobile experience. Developers can code the PWA to allow a shopper who is on an AMP page to tap a link and then be connected to another, pre-cached AMP page, maintaining extremely fast load speeds because the shopper is going to another optimized page, and not redirected to the mobile website. Plus, all of the AMP pages live under a PWA umbrella, meaning the consumer still gets the benefits of a progressive web app, such as full-screen mode, offline access, a consistent header and smooth navigation.

Both of these technologies, however, cost tens of thousands of dollars, or more, to develop and maintain.