Peerchat is a peer to peer chat application that runs in a browser. It relies on WebRTC, a technology for browser to browser communication.
A sample server can be found here.
Peerchat needs a signalization server to manage users and to initiate connections. This server is a tiny Node.js script which also serves the static HTML files required by the application. Launch this server with npm start.
You can deploy the application on Heroku for free.
You can deploy the application on Google App Engine Flex (websockets are not supported on standard environment). Just run gcloud app deploy.