A native iOS and macOS client for Subsonic, OpenSubsonic, and Navidrome servers. Built for people who self-host their music.
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Cassette is a native Swift / SwiftUI music client for iOS and macOS, built for people who run their own music server. It speaks the Subsonic and OpenSubsonic API, so it works with Navidrome and any other compliant server.
It's a pure streaming client for your library — no accounts, no subscriptions, no tracking. Your music stays between your device and your server. The iOS app is distributed via TestFlight; the macOS app ships as a notarized build through Homebrew.
Licensed under MPL-2.0.
Listening
- Native iOS 26 / macOS 15 client with a Liquid Glass design language
- Background playback with lock screen and Control Center controls, plus AirPlay
- True offline mode: download albums, playlists, or individual tracks
- Playback powered by the AudioStreaming engine — FLAC, MP3, AAC, WAV, and Ogg/Vorbis
- Persistent playback session — pick up where you left off after relaunching
- Lyrics support
- Shuffle, repeat, and full queue management
Library
- Browse by playlists, artists, albums, downloads, and favorites
- Pinned albums and playlists on the home screen
- Recently added (online) and recently downloaded (offline)
- Full-text search across your library
- Favorites synced with your server (star / unstar)
- Cassette Wrapped — a yearly recap of your listening
Integrations & extras
- ListenBrainz — scrobble your listens and surface recommendations (fresh releases, similar artists)
- Home-screen widgets (iOS)
- Discord Rich Presence — experimental / pre-alpha; shows your now-playing in Discord through the companion helper, cassette-discord-rpc
Server & privacy
- Subsonic and OpenSubsonic API, with OpenSubsonic extensions where available
- Custom HTTP headers for servers behind a reverse proxy (Cloudflare Access, Authelia, etc.)
- Credentials stored only in the iOS / macOS Keychain — zero tracking, zero analytics, all traffic direct to your server
brew tap MathieuDubart/cassette
brew install --cask cassetteThis installs the notarized Cassette.app.
Join the beta: https://testflight.apple.com/join/pxCpfpxF
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Requirements
- macOS 15 or later with Xcode 26 or later
- A Subsonic / OpenSubsonic / Navidrome server to connect to
- An Apple Developer account (the free tier works for personal device builds)
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Clone and open
git clone https://github.com/MathieuDubart/cassette.git cd cassette open Cassette.xcodeprojSwift Package Manager resolves the dependencies (SwiftSonic and AudioStreaming) automatically — no extra setup.
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Sign and run
- Select your team in Signing & Capabilities
- Choose an iOS 26+ device/simulator or My Mac
- Build and run (⌘R)
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First launch
- Cassette prompts for your server URL, username, and password
- If your server sits behind a reverse proxy that needs custom request headers, expand Advanced and add them
- Tap Connect — Cassette verifies the connection and stores credentials in the Keychain
- iOS 26 or later, or macOS 15 (Sequoia) or later
- A running Subsonic, OpenSubsonic, or Navidrome server
Cassette works with any server that implements the Subsonic / OpenSubsonic API, and uses OpenSubsonic extensions where available. Navidrome is the recommended and primary-tested server.
If your server implements the Subsonic API and something doesn't behave, open an issue.
For developers curious about the internals:
- UI — SwiftUI views with
@Observable @MainActorview models; no business logic in views. - Services — Swift actors (
PlayerService,LibraryService,DownloadService,FavoritesService,NowPlayingService, …) with no SwiftUI / UIKit imports. - Playback — the AudioStreaming engine, wired to
MPNowPlayingInfoCenterandMPRemoteCommandCenterfor lock screen, Control Center, and AirPlay. - Subsonic API — SwiftSonic (same author, separate repo, MIT) handles all Subsonic / OpenSubsonic communication.
- Persistence — SwiftData for app data (downloads, playlists, favorites cache); Keychain for credentials.
- Concurrency — Swift 6 strict concurrency,
Sendablethroughout,SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor. - Dependencies — SwiftSonic and AudioStreaming (which brings Ogg/Vorbis binary frameworks for lossless decoding). That's the full list.
Cassette is built incrementally, one theme per release.
- v1.8 — Widgets ✅ shipped
- v2.0 — CarPlay (in progress)
For the full roadmap and discussion, see GitHub Discussions.
- Website — getcassette.app
- Feedback / bug reports — [email protected] · GitHub Issues
- Ideas & discussion — GitHub Discussions
- Support development — Ko-fi
Contributions are welcome. A few things before you start:
- Discuss before coding — open an issue or discussion before working on a feature, especially architectural changes. A PR that contradicts a design decision may be closed.
- Match the existing style — Swift 6 strict concurrency, no Foundation / UIKit leakage outside the service layer, dependencies kept minimal (SwiftSonic + AudioStreaming).
- Test on real devices — audio playback and Liquid Glass effects behave differently in the Simulator.
- Conventional commits —
feat,fix,refactor,docs,chore, etc.
Cassette is licensed under MPL-2.0.
- You can use, study, modify, and redistribute the source.
- Modified files stay under MPL-2.0; you may combine them with proprietary code in a Larger Work.
- The distributed builds (Homebrew, TestFlight) are the same source, signed for convenience.
Dependencies: SwiftSonic (MIT) and AudioStreaming by Dimitris C. (MIT) — both compatible with MPL-2.0.
Code prior to commit 21f9227 was licensed under GPL-3.0-or-later.
- The Navidrome team for an excellent self-hosted music server
- The OpenSubsonic community for modernizing the Subsonic API
- Substreamer, Ultrasonic, and Symfonium for raising the bar on what a self-hosted music client should feel like
Built by Mathieu Dubart.
