Yes, Movim and Converse.js are two web-based XMPP apps that support installation as a PWA. XMPP supports running over websockets (or even long-polling HTTP, bu

Yes, Movim and Converse.js are two web-based XMPP apps that support installation as a PWA. XMPP supports running over websockets (or even long-polling HTTP, but that's thankfully less necessary these days).