What is an *arr stack?
The Servarr library managers, indexer managers, and download clients that make up a self-hosted media stack, and where Kochab fits.
“*arr” is the shared naming pattern behind Sonarr, Radarr, Lidarr, and the rest of the Servarr project, plus community apps built to the same shape - separate apps, each managing a single kind of media library. A stack is those apps plus the indexer-manager and download-client services that support them, usually running together on one machine.
The pieces
| Piece | Job | Examples |
|---|---|---|
| Library manager (*arr app) | Decides what belongs in your library, tracks what is missing, picks a release, hands it to a download client | Sonarr, Radarr |
| Indexer manager | Holds your indexer credentials and searches them through one endpoint | Prowlarr, Jackett |
| Download client | Fetches the release the library manager picked | SABnzbd, qBittorrent |
| Media server | Plays what has been imported into the library | Plex, Jellyfin |
| Request layer (optional) | Lets other people ask for a title without touching Sonarr or Radarr directly | Seerr |
Each piece is a separate service with its own API, web UI, and port. See Add and configure a service for the full list of what Kochab connects to.
How a title moves through the stack
- A title gets marked wanted - by you, or by someone else through Seerr.
- The library manager asks its configured indexer manager(s) for matching releases and picks one against its quality profile.
- It sends that release to a download client.
- When the download finishes, the library manager imports it into the library.
- The media server serves it.
Indexer manager and download client are two different jobs done by two different services - see Why is an indexer separate from a download client? for why that split exists.
Where Kochab fits
Kochab is a controller for the stack, not a part of it: it talks straight to each service’s own API rather than adding a server of its own in the middle. See Getting started for how connecting a service works and how Kochab blends data across everything you have configured.
Add and configure a service and the Service setup guides cover connecting each piece by name.