Build professional VST® 3 plugins and hosts with Flutter UI and pure Dart audio processing.

VST® is a trademark of Steinberg Media Technologies GmbH, registered in Europe and other countries.

This toolkit enables developers to create professional VST® 3 audio plugins with modern Flutter UIs while leveraging the power of pure Dart for real-time audio processing. Zero C++ knowledge required.

The toolkit compiles Dart code to native machine code executables that communicate with the VST® 3 wrapper via IPC (Inter-Process Communication). This provides true native performance without requiring the Dart runtime in the DAW.

graph TB subgraph "DAW Integration" DAW1[Ableton Live] DAW2[FL Studio] DAW3[Reaper] DAW4[Other VST® 3 Hosts] end subgraph "flutter_vst3 Toolkit" subgraph "VST Creation" FR[flutter_reverb<br/>Flutter VST® Plugin] ECHO[echo<br/>Flutter VST® Plugin] FVST[flutter_vst3<br/>VST® Building Framework] end subgraph "VST Hosting" DVH[dart_vst_host<br/>Load & Control VSTs] DVG[dart_vst_graph<br/>Audio Routing & Mixing] end subgraph "Native Bridge" NL[C++ VST® 3 Implementation<br/>Built via CMake] PL[VST® 3 Plugin Wrapper<br/>+ IPC to Dart Executable] end end subgraph "External VSTs" VST1[TAL Reverb] VST2[Other VST® 3 Plugins] end %% VST Creation Flow FR --> FVST ECHO --> FVST FVST --> PL PL --> NL %% VST Hosting Flow VST1 --> DVH VST2 --> DVH DVH --> DVG DVG --> NL %% DAW Integration NL --> DAW1 NL --> DAW2 NL --> DAW3 NL --> DAW4 style FR fill:#e1f5fe style ECHO fill:#e1f5fe style FVST fill:#e1f5fe style DVH fill:#fff3e0 style DVG fill:#fff3e0 style NL fill:#f3e5f5 style PL fill:#f3e5f5 

sequenceDiagram participant DAW participant VST3[VST® 3 Plugin (C++)] participant IPC[Binary IPC Protocol] participant DART[Dart Native Executable] participant UI[Flutter UI Window] Note over VST3,UI: Plugin Initialization VST3->>DART: Spawn dart_processor executable DART->>VST3: ACK ready VST3->>UI: Create Flutter window UI->>DART: Connect parameter binding Note over DAW,UI: Audio Processing DAW->>VST3: Process audio buffer VST3->>IPC: Send binary audio data IPC->>DART: Deserialize & process DART->>IPC: Return processed audio IPC->>VST3: Binary response VST3->>DAW: Return processed buffer Note over DAW,UI: Parameter Changes (3-way binding) DAW->>VST3: Set parameter VST3->>DART: Send parameter update DART->>UI: Notify UI of change UI->>UI: Update knobs/sliders 

Primary Purpose: Build VST® 3 plugins with Flutter UIs that compile to .vst3 bundles

• flutter_vst3 - Complete framework that auto-generates all C++ VST® 3 boilerplate from Dart
• vsts/flutter_reverb - Example VST® 3 reverb plugin with Flutter UI
• vsts/echo - Example VST® 3 echo/delay plugin with Flutter UI
• Native Executable Compilation - Dart compiles to native machine code (no runtime required)

Primary Purpose: Load and control existing VST® 3 plugins from Dart applications

• dart_vst_host - High-level API for loading and controlling VST® 3 plugins
• dart_vst_graph - Audio graph system for routing and mixing VST® plugins

• VST® 3 native components - C++ implementation using Steinberg VST® 3 SDK (built via CMake)
• Plugin wrappers - VST® 3 plugin wrappers that host Dart audio processing

• ✅ Beautiful Flutter UIs - Modern, reactive plugin interfaces
• ✅ Pure Dart DSP - Write audio algorithms in familiar Dart syntax
• ✅ Hot Reload - Instant UI updates during development
• ✅ 3-Way Parameter Binding - DAW ↔ Flutter UI ↔ C++ parameters stay in sync
• ✅ Zero C++ Required - Framework auto-generates all VST® 3 boilerplate

• ✅ Native Machine Code - Dart compiles to native executables
• ✅ No Runtime Overhead - No Dart VM or JIT in production
• ✅ Process Isolation - Plugin crashes won't affect DAW
• ✅ Small Binary Size - Minimal footprint in DAW

• ✅ macOS - Universal binaries (Intel + Apple Silicon)
• ✅ Windows - Native Windows VST® 3 support
• ✅ Linux - Full Linux VST® 3 support

# Download Steinberg VST® 3 SDK ./setup.sh # Automatically downloads SDK and builds native libraries # Or manually set VST3_SDK_DIR export VST3_SDK_DIR=/path/to/vst3sdk

1. Build the example plugins:

# Build Flutter Reverb VST® 3 (default) make # Build specific plugins: make reverb-vst # Build flutter_reverb.vst3 make echo-vst # Build echo.vst3 # Install to system VST folder make install

2. Test in your DAW:

• macOS: ~/Library/Audio/Plug-Ins/VST3/
• Windows: C:\Program Files\Common Files\VST3\
• Linux: ~/.vst3/

1. Define parameters with Flutter UI bindings:

// lib/src/my_parameters.dart class MyParameters { /// Controls the output volume (0% = silence, 100% = full volume)  double gain = 0.5; /// Adds warmth to the signal (0% = clean, 100% = saturated)  double warmth = 0.0; }

2. Implement your audio processor:

// lib/src/my_processor.dart class MyProcessor { void processStereo(List<double> inputL, List<double> inputR, List<double> outputL, List<double> outputR, MyParameters params) { for (int i = 0; i < inputL.length; i++) { outputL[i] = inputL[i] * params.gain; outputR[i] = inputR[i] * params.gain; } } }

3. Create Flutter UI with parameter binding:

// lib/my_ui_main.dart import 'package:flutter/material.dart'; import 'package:flutter_vst3/flutter_vst3.dart'; void main() { runApp(MyPluginUI()); } class MyPluginUI extends StatefulWidget { @override _MyPluginUIState createState() => _MyPluginUIState(); } class _MyPluginUIState extends State<MyPluginUI> { final parameters = MyParameters(); @override void initState() { super.initState(); // Register for DAW parameter changes VST3Bridge.registerParameterChangeCallback(_onParameterChanged); } void _onParameterChanged(int paramId, double value) { setState(() { parameters.setParameter(paramId, value); }); } void _updateParameter(int paramId, double value) { setState(() { parameters.setParameter(paramId, value); }); // Send to VST host/DAW VST3Bridge.sendParameterToHost(paramId, value); } @override Widget build(BuildContext context) { return MaterialApp( home: Scaffold( body: Column( children: [ Text('My VST Plugin'), Slider( value: parameters.gain, onChanged: (v) => _updateParameter(0, v), ), ], ), ), ); } }

4. CMake automatically generates everything else!

import 'package:dart_vst_host/dart_vst_host.dart'; import 'package:dart_vst_graph/dart_vst_graph.dart'; void main() async { // Initialize host final host = VstHost(); await host.initialize(); // Load VST plugin (including Flutter-based VSTs!) final plugin = await host.loadPlugin('flutter_reverb.vst3'); // Create audio graph final graph = VstGraph(); final pluginNode = graph.addVstNode(plugin); final mixerNode = graph.addMixerNode(); // Connect nodes graph.connect(pluginNode.output, mixerNode.input1); // Start processing await graph.start(); }

flutter_vst3_toolkit/ ├── flutter_vst3/ # Framework for building VST® 3 plugins with Flutter │ ├── lib/ │ │ ├── flutter_vst3.dart │ │ └── src/ │ │ ├── flutter_vst3_bridge.dart # DAW ↔ Flutter binding │ │ ├── flutter_vst3_callbacks.dart # FFI callbacks │ │ └── flutter_vst3_parameters.dart # Parameter management │ ├── native/ # C++ templates and CMake helpers │ └── scripts/ # Plugin generation scripts ├── vsts/ │ ├── flutter_reverb/ # Example reverb with Flutter UI │ └── echo/ # Example echo with Flutter UI ├── dart_vst_host/ # VST® 3 hosting API for Dart ├── dart_vst_graph/ # Audio graph system ├── vst3sdk/ # Steinberg VST® 3 SDK └── Makefile # Build automation 

1. Design UI in Flutter with hot reload
2. Implement audio processing in pure Dart
3. Test with flutter run
4. Build VST® 3: make echo-vst
5. Load in DAW and test

The framework provides automatic 3-way parameter binding:

• DAW → Flutter UI: Parameter changes in DAW update Flutter UI
• Flutter UI → DAW: UI interactions update DAW parameters
• Flutter UI → Processor: UI changes update audio processing

• Full reverb algorithm in pure Dart
• Real-time parameter updates
• Ships as standard .vst3 bundle

• Delay/echo effect with feedback
• Bypass control
• Parameter automation support

# Run all tests make test # Test individual packages cd flutter_vst3 && dart test cd vsts/echo && dart test cd dart_vst_host && dart test cd dart_vst_graph && dart test # Interactive testing with example plugins cd vsts/flutter_reverb && flutter run

This toolkit is designed for professional audio development. Contributions should maintain:

• No duplication: Use existing components
• No placeholders: Implementation must be complete
• Pure FP style: Immutable data, pure functions
• Flutter-first: Leverage Flutter's UI capabilities
• Clear documentation: All public APIs documented

This project is not affiliated with, endorsed by, or sponsored by Steinberg Media Technologies GmbH. VST® is a trademark of Steinberg Media Technologies GmbH, registered in Europe and other countries.

The flutter_vst3 Toolkit interfaces with the Steinberg VST® 3 SDK under the terms of the VST® 3 SDK License Agreement. Users must comply with the Steinberg VST® 3 SDK License Agreement when distributing VST® 3 plugins.

For more information about VST® 3 licensing: https://steinbergmedia.github.io/vst3_dev_portal/pages/VST+3+Licensing/Index.html

See LICENSE file. Commercial use requires compliance with Steinberg VST® 3 licensing terms.

Ready to build the next generation of audio plugins with Flutter and Dart? Start with the examples and unleash your creativity!