AMP pre-rendering

AMP pre-rendering deserves a special mention here. It's used to boost the loading time of pages in the AMP cache. With AMP-HTML and AMP-JS, you get fast web pages. But with pre-rendering, you get instant pages.

Pre-rendering works by using a hidden iframe to download and render AMP pages in the background, even before the user has decided to visit them. The embedding page loads a hidden iframe with the AMP page content. The browser then loads the AMP runtime and starts to render the page. Since the AMP runtime manages resource loading, nothing else is loaded by the browser at this point (although the AMP runtime might decide to download necessary above-the-fold resources).

If the user clicks a pre-rendered AMP link, all the work to render the page has already been completed, so it can be displayed instantly simply by making the iframe visible. The JavaScript component that manages the pre-rendering iframe is called the AMP Viewer.