Radarr is an open-source, self-hosted tool designed to automate the process of managing and downloading movies. It allows users to track movies they want to watch and automatically fetch them from Usenet or BitTorrent sources once they are available in the desired quality. Radarr offers features like the ability to set custom quality preferences, automatically rename downloaded files, and integrate with media servers like Plex or Emby for seamless media management. With its simple, intuitive interface, Radarr is ideal for users looking to automate their movie collection while ensuring everything is organized and easily accessible.