It depends on the technology that you use. You will probably need a small public service, yes even when you're doing WebRTC. With a project like https://oxism.

It depends on the technology that you use. You will probably need a small public service, yes even when you're doing WebRTC. With a project like https://oxism.com/trystero https://oxism.com/trystero you could piggyback it on top of a public decentralized service like Nostr.