Prowlarr and Jellyseerr are two tools you use together.

Prowlarr is an index manager, for Radarr and Sonarr. With Radarr and Sonarr, generally you’d have to provide individual indexes (in the case of torrents, trackers) for each individual instance of Radarr and Sonarr. With Prowlarr, you basically have a central database of trackers, organized by tags (like movies or TV shows), that will then feed that information to Radarr and Sonarr.

Jellyseerr is like the requesting interface. If you want to watch a show or movie, you place a request with Jellyseerr, that gets sent over to Radarr or Sonarr, and then either instance will then search for the content using the indexes provided by Prowlarr. Radarr or Sonarr will then begin the download, and then organize it within your media files.