Automated Lossless Music Discography Downloader, Tagger, and Library Manager.
fnack is a lightweight, self-hosted service that downloads, tags, and organizes complete artist discographies into your music library. It runs as a single container, and works with your media server (Navidrome, Plex, Jellyfin, Subsonic).
Zero authentication required. fnack resolves and downloads tracks without any Spotify, Tidal, Qobuz, or YouTube account.
- Lossless downloads with smart fallback — true lossless FLAC when available; if a track can't be downloaded losslessly, fnack falls back to high-quality extraction from YouTube / YouTube Music.
- One-click discography sync — add an artist and fnack finds their albums and tracks, resolves each song, downloads it, tags it, and files it into your library.
- Verified before it's accepted — every download is checked against the official release (duration + embedded tags, plus optional fingerprinting) before it reaches your library; wrong-song or corrupted downloads are rejected automatically.
- Library management — overview stats, one-click retry of failed tracks, parallel folder import, manual match & track fixer, per-track monitoring.
- Media-server friendly — can trigger a rescan on your media server when downloads finish.
The repository ships a ready-to-use docker-compose.yml that works on any
machine — with or without git (a prebuilt image is published to GHCR on every
push; you can also build locally). First run:
cp .env.example .env # then edit MUSIC_PATH to your music library
docker compose up -d # pulls the prebuilt image (GHCR)
# or build locally: docker compose up -d --buildDeploying to another machine without git is just as easy — see DEPLOY.md for the one-file release bundle and offline options.
docker run -d --name fnack \
-v ./config:/config -v ./downloads:/downloads -v /path/to/music:/music \
-p 4688:4688 fnack:latestAccess the web interface at http://<server-ip>:4688. On first boot you
are asked to create an admin account (/setup) — the whole app is behind
a login until then (passwords are stored salted + hashed). Optional machine
access via the M2M API key in Settings.
Configuration is split into core settings (fnack itself) and plugin-owned settings (each plugin's own preferences). Core settings:
| Setting | Default | Description |
|---|---|---|
max_concurrent |
1 |
Maximum simultaneous track downloads |
music_path |
/music |
Target directory for organized music library |
matching_strictness |
standard |
Duration tolerance: strict (±4s), standard (±8s), lenient (±15s) |
enable_duration_check |
true |
Set false to skip duration verification and accept any downloaded audio |
Plugin settings are managed from Settings → Plugins: each plugin owns its own settings, state, and cache — core has none. (Legacy flat settings from older versions are read once as a migration fallback and moved into the owning plugin; the plugin setting is authoritative.)
fnack is built on a small plugin system: the core orchestrates capabilities — e.g. download a track, search an artist, scan a media server — and plugins provide them. The Docker image ships with the plugins needed for the default out-of-box experience (Spotify + YouTube downloads and discography sync); everything else is optional.
- Optional official plugins — fingerprinting, media-server scans, VPN, notifications, and more — are one click away in Settings → Plugins → Marketplace.
- Community plugins are installed the same way, can replace any official provider for the same capability, and need no core change.
See docs/plugins/AUTHORING.md for writing your own plugins.
- YouTube
cookies.txtSetup — fix bot-checks / sign-in blocks on YouTube downloads. - VPN Setup (Optional) — route downloads through a VPN tunnel running inside the container.
- Deployment
- Plugin authoring
- Architecture — for developers
This project is licensed under the MIT License. See LICENSE for details.