I built an expo-module that makes it easy to integrate CallKit/Core-Telecom into a React Native app. I've built a VoIP app before and this was one of the hardest parts. The existing react-native-callkeep is harder to use, isn't easy to set up VoIP notifications with and hasn't been updated in two years. This new module is tested with the latest versions of iOS/Android, Expo and LiveKit. It has a simple and unified API across iOS/Android.