Radarr is an automated movie collection manager that monitors and downloads movies for you. It keeps track of movies on your watchlist (which can be populated from various sources like Trakt or IMDb lists) and scans your configured indexers for available releases. When a movie is found that matches your specified quality profiles, Radarr automatically sends it to your download client (like qBittorrent or SABnzbd). Once the download is finished, Radarr handles the rest by renaming the file according to your rules, moving it to your movie library folder, and notifying your media server to pick up the new content. It also has the ability to automatically upgrade existing movies in your library to a higher quality version when one becomes available.