Pulsarr

Pulsarr: Real-time Plex watchlist monitoring and content acquisition tool. Seamlessly sync Plex watchlists with Sonarr and Radarr, featuring intelligent predicated content routing, multi-instance support, Discord, and Apprise notifications. Automate your media library management with a modern, user-friendly interface. Maintained by jamcalli on GitHub, where it has earned 740 stars from the community.

It's actively developed around arrs, automation, discord-bot, and is a solid reference for anyone building with these tools.