> But I'm assuming it can't break through all NAT routers, right? A good portion of people still won't be able to use this?

> A service usable by everyone would require STUN and TURN servers to be set up, no?

Anecdata, of course, but I haven't been able to reliably use any of these WebRTC based file transfer services (file.pizza, instant.io, etc etc). Testing mostly between two computers on the same subnet. Sometimes they work for a little while, at surprisingly low speeds (for two computers connected to the same wireless access point), sometimes I can let them sit for an hour and never get a connection. I've learned to not even bother trying them, it just wastes time.

That said, magic-wormhole (the original) works fine between the same devices, so maybe I'll see if something is somehow different about this implementation.

Edit: ah yes, this service hangs indefinitely on "connecting". You love to see it. (Firefox on Linux - firewall disabled specifically for this test - and Safari on macOS)

Edit: seems to be working in Chrome (Linux) to Firefox (Android). Not sure what the difference is.