Compatibility
Houndarr talks to your *arr instances through their REST APIs (v3 for Radarr, Sonarr, and Whisparr; v1 for Lidarr and Readarr). The table below lists the versions currently tested against.
Tested versions
| Application | API version | Tested with |
|---|---|---|
| Radarr | v3 | 6.0.4.10291 |
| Sonarr | v3 | 4.0.17.2952 |
| Lidarr | v1 | 3.1.0.4875 |
| Readarr | v1 | 0.4.20.129 |
| Whisparr v2 | v3 | 2.2.0.108 |
| Whisparr v3 | v3 | 3.3.2.604 |
Whisparr v2 and v3 are separate applications with different APIs.
v2 is Sonarr-based (studio / episode model, Docker:
hotio/whisparr:latest). v3 is Radarr-based (scene / movie model,
Docker: hotio/whisparr:v3). Select the matching instance type in
Houndarr.
Any version that exposes the same API (v3 or v1 depending on the
app) should work. When you test a connection, Houndarr reads the
appName and version from the instance's system/status endpoint
and verifies it matches the type you selected. For Whisparr, it
also detects v2 / v3 version mismatches.
Readarr forks
The original Readarr project was discontinued in June 2025. Community forks that use the same v1 API are expected to work when configured as type Readarr:
Forks that return an unrecognized appName in their system / status
response still connect; the type check only rejects known
mismatches (for example pointing a "Radarr" config at a Sonarr
URL).