Instruction 07-connecting-prowlarr-to-sonarr-and-radarr: Reading

Prowlarr centralizes indexer management while Sonarr and Radarr remain responsible for monitoring titles, selecting releases, and sending downloads to a download client. Connecting the applications does not merge their libraries or transfer media files. Instead, Prowlarr authenticates to the Sonarr and Radarr APIs and creates compatible indexer definitions for them.

The most important addressing rule is that an application URL must work from Prowlarr's network context. A URL that opens in an administrator's browser is not automatically usable by Prowlarr. For example, http://localhost:8989 means the system or container making the request. If Prowlarr and Sonarr are separate containers, localhost inside Prowlarr refers to Prowlarr itself rather than Sonarr. On a shared container network, a service name such as http://sonarr:8989 is often appropriate. If services use host networking, separate systems, or a reverse proxy, the correct address may instead be a host address or internal DNS name. The same rule applies to Radarr on its configured port.

The Prowlarr URL has the opposite direction of concern: it must be usable by Sonarr or Radarr when they query an indexer managed through Prowlarr. Internal service names are generally preferable when all participants share the same trusted network. Public proxy addresses can work, but they add dependencies involving DNS, TLS certificates, authentication middleware, and proxy routing. Base URLs must be represented consistently. If Sonarr is configured with /sonarr, an address that omits that path may reach a proxy but still return a not-found response.

To prepare a real connection, retrieve the API key from the target application's General settings and treat it as a credential. In Prowlarr, open Settings, then Apps, add the appropriate Sonarr or Radarr application type, enter a descriptive name, synchronization level, application URL, Prowlarr URL, and the target application's API key. Use the Test action before Save. A successful test confirms basic addressability, API authentication, and API compatibility; it does not prove that every indexer supports the desired media categories.

Tags control scope. With no restrictive tags, eligible indexers can be synchronized broadly. If an application entry has tags, only appropriately tagged indexers are selected. This is useful when one tracker should provide television results but not movie results, or when separate applications require different indexer policies. A tag mismatch can therefore produce an apparently healthy application connection with no useful synchronized indexers.

Full Sync gives Prowlarr stronger authority over managed indexer definitions. Changes made directly to a Prowlarr-managed indexer in Sonarr or Radarr may be overwritten during a later synchronization. Add and Remove Only is useful when local tuning should remain under the target application's control, although exact options can vary by release. Choose ownership deliberately instead of treating the sync level as a cosmetic setting.

After saving a production integration, inspect the target application's Indexers page and identify the entries managed through Prowlarr. Run a test from the target application, then perform an interactive search for a known monitored title. Do not immediately enable automatic searching across a large library. A staged check makes authentication, category, rate-limit, and quality-profile mistakes easier to isolate. This lesson's executable lab does not alter live applications; it builds and validates an integration plan entirely under the required classroom directory.