The names sound like a pirate convention. Sonarr, Radarr, Prowlarr, Jackett, Bazarr. Once you understand what each one actually does, it stops being confusing and starts being one of the more satisfying pieces of automation in a homelab.
What the stack actually does
You add a show or a movie to a watchlist. Some time later, it shows up in your media library already downloaded, organized, and renamed properly. No manual searching, no manually renaming files at 11pm because your media server refuses to recognize “movie.720p.FINAL2.mkv” as anything at all.
The pieces
Every version of this stack starts with an indexer layer, something that knows where to look for a release. Prowlarr is the current default recommendation for this job, since it syncs its indexer list directly into Sonarr and Radarr instead of making you configure indexers in multiple places. Jackett does the same basic job and predates Prowlarr, still works fine, and plenty of existing setups run it simply because it was already there first.
Sonarr handles TV shows. Radarr handles movies. Same underlying idea for both: you tell it what you want, it searches your indexers, picks the best quality match based on rules you set, and hands the file off to a download client, usually qBittorrent or Deluge.
From there the optional layer starts. Bazarr finds and downloads matching subtitles automatically. Overseerr gives everyone else in the house a clean interface to request something without needing direct access to Sonarr or Radarr, which cuts down on the “can you download this for me” texts. Neither is required to make the core loop work, but both solve real annoyances once the basics are running.
Setting it up without losing a weekend
Start with your indexer manager, whichever one you pick. Get indexers added and tested there first, since everything downstream depends on it working. Then add Sonarr and Radarr, pointing each at your indexer manager using the API key each app shows under Settings, General. Once those are talking to each other and to your download client, the automation starts running itself. Add Bazarr and Overseerr later, once the core loop is solid.
Docker Compose is the sane way to run all of this. One file, every service defined, and you can tear the whole stack down and rebuild it in minutes if something breaks. Most modern Synology and QNAP boxes handle Docker fine, so it does not require a dedicated machine.
The honest warning
This stack is genuinely addictive to tune. You will find yourself adjusting quality profiles at midnight for a show you are not even watching yet. Set your rules once, walk away, and let it do its job. That is the entire point, even when getting there takes longer than you planned.
Part of a bigger project
The Arr stack is one piece of our Home Media Server project. Full build log and specs are over there. If you are fighting with your own indexer setup or want to compare quality profiles, swing by The Bench and we will figure it out together.