https://2023.elixirconf.com/presenters#speaker-michal-sledz-elixirconf-us-2023 Pion is currently the most popular, open-source WebRTC implementation written in Go. It’s a base of the awesome Livekit media server, known for its usage in Spotify. In the era of rewriting everything in Rust, I rewrote Pion in Elixir. In this talk, I will present the results of my recent work focusing on three basic protocols used in WebRTC and VoIP, namely STUN, TURN, and ICE. The main aspects I am going to cover are the theoretical introduction into the domain, architecture of the ICE library and TURN server, performance comparison with Pion (Go) and coTURN (C), challenges in implementing RFC documents in a functional language, and a couple of examples showing the API of my libraries and their integration with Pion.