A calm audio player for kids. No algorithm, no rabbit holes.

What's lauschi?

lauschi wraps audio providers behind a curated, card-based interface for children. Parents build visual content cards; kid taps a card, audio starts. No recommendations, no autoplay, no screen time spiral.

Currently supports ARD Sounds (formerly ARD Audiothek, free, no account needed), Spotify and Apple Music. Built with Flutter. DACH-market focus (Hörspiele, Kindermusik), internationalizable. All data stays on-device.

Status

MVP functional on Android and iOS. Grouping, catalog matching, NFC tag support, parent/kid modes working. Catalog curation pipeline covers ~120 DACH Hörspiel and music series.

Setup

Requires mise for tool management.

git clone git@github.com:EnTeQuAk/lauschi.git
cd lauschi
mise install                    # Flutter, Java 17, gh, uv
cp .env.example .env            # developer keys for scripts
cp .env.app.example .env.app    # app build config
mise run setup                  # flutter pub get + codegen
mise run dev                    # run on connected device

Environment

Two env files (both gitignored):

• .env — Developer keys for tooling. Loaded by mise. Not passed to Flutter.
• .env.app — App build config. Passed to Flutter via --dart-define-from-file.

.env.app:

ENABLE_SPOTIFY=false            # feature flag
SPOTIFY_CLIENT_ID=...           # required when Spotify enabled
SENTRY_DSN=...                  # optional, error tracking
SENTRY_ENVIRONMENT=development

ARD Sounds works out of the box with no credentials, no account. Free public broadcaster content. The app uses the ARD Sounds GraphQL API (still at api.ardaudiothek.de, the service's name until March 2026) to browse and stream children's audio content directly.

Spotify requires a client ID (PKCE flow, no client secret). Create a Spotify app at https://developer.spotify.com/dashboard, add lauschi://callback as a redirect URI, and copy the client ID.

For catalog curation tools (optional, not needed to build/run the app):

OPENCODE_API_KEY=...            # for AI curation scripts
BRAVE_API_KEY=...               # for catalog review web search

Architecture

• Flutter + Dart: iOS and Android from one codebase
• Riverpod 3: state management
• Drift: local SQLite with schema migrations
• Spotify Web Playback SDK: Spotify audio via hidden WebView (EME/DRM). The SDK's player.html is hosted externally (requires HTTPS origin for Widevine). See lib/core/spotify/spotify_config.dart for the URL.
• ARD Sounds GraphQL API + just_audio: free streaming of public broadcaster content (no account required)
• go_router: navigation with parent PIN gate
• very_good_analysis: strict linting
• Sentry: crash reporting + session replay (EU region)
• AI-assisted catalog curation: pydantic-ai agents in tools/, one model curates and a second model of another family audits. A person settles what they disagree on.

Catalog curation

The catalog is a developer-side build product. AI models help sort through thousands of store albums, no AI runs in the app itself, and no AI-generated content is shown to kids. A second model audits every curation, and a person settles what the two disagree on.

The app ships assets/catalog/series.json: every series with its titles, episode pattern, artist ids and the curated albums per store (id, episode number, title, release date, barcode). It is written by the lauschi-catalog CLI and its web UI from the per-series curation state in assets/catalog/curation/*.json, so you change it through those tools rather than by hand.

mise run catalog-add -- "PAW Patrol"          # seed a new series
mise run catalog-pipeline-one -- paw_patrol   # curate, audit, apply, validate
mise run catalog-review                       # what needs a person
mise run catalog-web                          # the web UI

AGENTS.md ("Catalog Tools") describes every stage, the commands and how to evaluate a change to the curator.

Development

mise run dev                    # flutter run with .env
mise run test                   # flutter test
mise run analyze                # flutter analyze
mise run setup                  # pub get + codegen
mise run check                  # format + analyze + test (CI equivalent)

Building for Android

Prerequisites:

• Android SDK (install via mise install or Android Studio)
• Java 17 (installed by mise)
• A connected Android device or emulator with API 24+

# Debug APK
mise run build                  # builds APK with codegen + .env

# Install on connected device
flutter install --debug

# Or run directly
mise run dev

The debug APK lands in build/app/outputs/flutter-apk/app-debug.apk.

For release builds, you'll need a signing key configured in android/app/build.gradle. See the Flutter Android deployment docs.

Testing on Android

# Run all tests
mise run test

# Run a single test file
flutter test test/core/catalog/catalog_service_test.dart --dart-define-from-file=.env.app

# Run with coverage
flutter test --coverage --dart-define-from-file=.env.app

Tests don't require a device and run on the Dart VM. Integration tests (Patrol) require a connected device or emulator.

iOS

iOS builds require macOS with Xcode. The project uses Codemagic for CI/CD on iOS. Local iOS development works with flutter run on a Mac with Xcode installed and an iOS 14.0+ device/simulator.

Contributing

1. Fork the repo and create a branch from main
2. mise install && mise run setup
3. Make your changes, run mise run check to verify
4. Open a PR. CI runs format, analyze, test, and debug build.

Keep commits focused and messages in imperative mood ("Fix bug" not "Fixed bug"). See the project's analysis_options.yaml for lint rules.

License

Copyright © 2025-2026 Christopher Grebs. Licensed under GPL-3.0.