I haven’t tried it, but looking at the source, but you should be able to simply clone the repo, run “npm install” and “npm run build” and deploy the output to a webserver.

I’ve looked at the traffic, and all calls go directly to the API of my instance. I don’t think Alexandrite even runs a backend.

It’s not exactly OAuth, but the webapp logs in at the chosen instance via its API and gets issued a JWT it uses for all subsequent requests.