The folks at Expo have made it really easy to build (and publish!) your React Native applications on their infrastructure, with their Expo Application Services (EAS) offering:
You can build your app with EAS Build and automatically submit to app stores with EAS Submit in minutes or less, thanks to automatically managed app signing credentials, automatic submissions, and defaults that just work for most Expo and React Native apps.
Internal distribution makes it easy to share test builds with colleagues and friends using ad hoc or enterprise provisioning on iOS and APK side-loading on Android.
Tested out a preview of the Free plan about a month ago and works pretty darn well. The first attempt wouldn’t build though, but a retrigger of eas build quickly fixed that 🙂