The Portals API enables making multiple websites work together by allowing seamless handovers between each website, in a UNIXy way (each site does something nar

The Portals API enables making multiple websites work together by allowing seamless handovers between each website, in a UNIXy way (each site does something narrow and specific). In short, the main thing Portals have over iframes is the ability to promote an iframe to become the top level website, and go back the other way around. You also get new APIs aiming at making the transition between two websites more seamless visually, and easier to integrate the functionality between the two. Check out the link I shared in the other comment for videos and further context.