Sonarr, Radarr and Prowlarr
What they are for. Sonarr handles TV, Radarr handles films, Prowlarr manages the indexers both of them search. Kustos reads their libraries to know what you hold, and writes monitoring, quality profiles and tags back when an arr rule acts.
Cost. Free, self-hosted. The key already exists — you are fetching it, not creating it.
All three keep the key in the same place.
Steps
- Open Sonarr (or Radarr, or Prowlarr) in a browser tab.
- Go to Settings → General.
- Find the Security block. API Key is there, usually masked.
- Press the copy button beside it, or reveal and select the value.
- In Kustos, go to Connections and find the matching card. If the service runs on this machine, Kustos has usually already detected it and filled the address in.
- Paste the key into API key, check the address is the one you use in your browser, and press Save.
- Repeat for the other two.
The address is the part that goes wrong. Use the address as your browser shows it. If Kustos runs in Docker and the arr does not, localhost inside the container is not the same machine as localhost in your browser.
A second instance. Add it as its own card. Kustos may label it 4K based on the port it found; that guess is often wrong and the label changes nothing about what Kustos sends, so turn it off if your second instance is for kids, anime, or another disk.
How you know it worked. The card turns green and reports a version number. Arr rules stop saying "unsupported".