Sonarr is a PVR for Usenet and BitTorrent users. It can monitor multiple RSS feeds for new episodes of your favorite shows and will grab, sort and rename them. It can also be configured to automatically upgrade the quality of files already downloaded when a better quality format becomes available.

Jackett works as a proxy server: it translates queries from apps (Sonarr, Radarr, SickRage, CouchPotato, Mylar, DuckieTV, etc) into tracker-site-specific http queries, parses the html response, then sends results back to the requesting software.

Radarr is an independent fork of Sonarr reworked for automatically downloading movies via Usenet and BitTorrent. The project was inspired by other Usenet/BitTorrent movie downloaders such as CouchPotato.