flutter_vst3 Toolkit

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.

Architecture Overview

VST® 3 Plugin Architecture with Native Dart Executable

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

Native Executable Implementation

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

Package Overview

🎛️ VST® 3 Plugin Creation

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 native sliders (no standalone Flutter app)
vsts/echo - Example VST® 3 echo/delay plugin with Flutter UI
Native Executable Compilation - Dart compiles to native machine code (no runtime required)

🎧 VST® Hosting Packages

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

🔧 Native Infrastructure

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

Key Features

Flutter UI + 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 Performance

✅ 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

Cross-Platform Support

✅ macOS - Universal binaries (Intel + Apple Silicon)
✅ Windows - Native Windows VST® 3 support
✅ Linux - Full Linux VST® 3 support (X11 desktop backend for GUI; run with GDK_BACKEND=x11)

Quick Start

Prerequisites

# macOS / Linux: Download Steinberg VST® 3 SDK & build native libraries
./setup.sh

# Windows (Command Prompt or PowerShell):
.\setup.bat   # or .\setup.ps1

Tip

If running .ps1 scripts in PowerShell gives an execution policy error, simply run .\setup.bat and .\build.bat, or allow local scripts once via Set-ExecutionPolicy -Scope CurrentUser RemoteSigned.

Building Your First VST® Plugin

Build the example plugins:

macOS / Linux:

# Build Flutter Reverb VST® 3 (default)
make

# Build specific plugins:
make reverb           # Build flutter_reverb.vst3
make echo             # Build echo.vst3

# Build, then copy to the folder VST3 hosts scan
make deploy           # Echo and Reverb
make deploy-echo      # Echo only (or: make -C vsts/echo deploy)
make deploy-reverb    # Reverb only (or: make -C vsts/flutter_reverb deploy)

Windows (PowerShell or Command Prompt):

:: Build Flutter Reverb VST® 3 (default)
./build.bat

:: Build specific plugins:
./build.bat reverb
./build.bat echo

:: Build native libraries only (dart_vst_host & dart_vst_graph)
./build.bat native

:: Build, then copy plugins to the user VST3 folder (%LOCALAPPDATA%\Programs\Common\VST3\)
.\build.bat deploy
.\build.bat deploy-echo
.\build.bat deploy-reverb

:: Clean build artifacts
.\build.bat clean

Note

.\build.bat deploy copies plugins to the standard user directory C:\Users\<user>\AppData\Local\Programs\Common\VST3\. It does not require Administrator privileges.

Test in your DAW:

macOS: ~/Library/Audio/Plug-Ins/VST3/
Windows: C:\Users\<user>\AppData\Local\Programs\Common\VST3\
Linux: ~/.vst3/

Important

Linux GUI Requirement: The standard VST3 windowing backend on Linux uses X11. Any application or host running VST3 plugins with a graphical interface on Linux must be launched with the GDK_BACKEND=x11 environment variable (e.g. GDK_BACKEND=x11 flutter run), otherwise the GUI will not be displayed on Wayland desktop sessions.

Creating Your Own VST® Plugin

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;
}

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;
    }
  }
}

Create Flutter UI with parameter binding:

// lib/my_ui_main.dart
import 'package:flutter/material.dart';
import 'package:flutter_vst3/ui.dart';

void main() {
  runApp(const MaterialApp(home: MyPluginUI()));
}

class MyPluginUI extends StatefulWidget {
  const MyPluginUI({super.key});

  @override
  State<MyPluginUI> createState() => _MyPluginUIState();
}

class _MyPluginUIState extends State<MyPluginUI> {
  static const gainParam = 0;
  final VST3ParameterBinding _binding = VST3ParameterBinding.getInstance();

  void _rebuild() => setState(() {});

  @override
  void initState() {
    super.initState();
    _binding.addListener(_rebuild);
    _binding.loadInitialParameters();
  }

  @override
  void dispose() {
    _binding.removeListener(_rebuild);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Slider(
        value: _binding.getParameter(gainParam),
        onChangeStart: (_) => _binding.beginEdit(gainParam),
        onChanged: (value) => _binding.setParameter(gainParam, value),
        onChangeEnd: (_) => _binding.endEdit(gainParam),
      ),
    );
  }
}

CMake automatically generates everything else!

Building a VST® Host Application

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();
}

Project Structure

flutter_vst3_toolkit/
├── flutter_vst3/           # Framework for building VST® 3 plugins with Flutter
│   ├── lib/
│   │   ├── flutter_vst3.dart   # DSP worker API
│   │   ├── ui.dart             # Flutter editor API
│   │   └── src/
│   │       ├── vst3_worker_loop.dart      # DSP worker over shared memory
│   │       └── parameter_binding.dart     # Editor ↔ DAW parameters
│   ├── 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

Development Workflow

VST® Plugin Development

Design UI in Flutter with hot reload
Implement audio processing in pure Dart
Test with flutter test; plugins with a Flutter entrypoint can also use flutter run
Build and deploy VST® 3: make deploy-echo
Load in DAW and test

Parameter Binding System

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

Examples in Production

Flutter Reverb Plugin

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

Echo Plugin

Delay/echo effect with feedback
Bypass control
Parameter automation support

Testing

# Run all tests
make test             # macOS / Linux
build.bat test        # Windows (or .\build.ps1 test)

# Test individual packages
(cd flutter_vst3 && flutter test)
(cd vsts/echo && flutter test)
(cd dart_vst_host && dart test)
(cd dart_vst_graph && dart test)

# Interactive testing with example plugins
# (On Linux, set GDK_BACKEND=x11 so native VST3 GUIs can be displayed)
# Reverb has no standalone app: build with make deploy-reverb and load in a VST3 host.
# On Linux:
(cd vsts/echo && GDK_BACKEND=x11 flutter run)

Contributing

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

Legal Notice

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

License

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!

Name		Name	Last commit message	Last commit date
.claude		.claude
.devcontainer		.devcontainer
.github		.github
.vscode		.vscode
dart_vst_graph		dart_vst_graph
dart_vst_host		dart_vst_host
docs		docs
flutter_vst3		flutter_vst3
mk		mk
vsts		vsts
.deslop.toml		.deslop.toml
.gitignore		.gitignore
AGENTS.md		AGENTS.md
CLAUDE.md		CLAUDE.md
GEMINI.md		GEMINI.md
Makefile		Makefile
README.md		README.md
VST_Compatible_Logo_Steinberg.png		VST_Compatible_Logo_Steinberg.png
build.bat		build.bat
build.ps1		build.ps1
coverage-thresholds.json		coverage-thresholds.json
setup.bat		setup.bat
setup.ps1		setup.ps1
setup.sh		setup.sh
validate_echo.sh		validate_echo.sh
validate_flutter_reverb.sh		validate_flutter_reverb.sh

Navigation Menu

Repository navigation

About

Repository files navigation

flutter_vst3 Toolkit

Architecture Overview

VST® 3 Plugin Architecture with Native Dart Executable

Native Executable Implementation

Package Overview

🎛️ VST® 3 Plugin Creation

🎧 VST® Hosting Packages

🔧 Native Infrastructure

Key Features

Flutter UI + Dart Audio Processing

Native Performance

Cross-Platform Support

Quick Start

Prerequisites

Building Your First VST® Plugin

Creating Your Own VST® Plugin

Building a VST® Host Application

Project Structure

Development Workflow

VST® Plugin Development

Parameter Binding System

Examples in Production

Flutter Reverb Plugin

Echo Plugin

Testing

Contributing

Legal Notice

License

About

Releases

Packages

Contributors

Languages

Latest commit

History

Folders and files

Repository files navigation

flutter_vst3 Toolkit

Architecture Overview

VST® 3 Plugin Architecture with Native Dart Executable

Native Executable Implementation

Package Overview

🎛️ VST® 3 Plugin Creation

🎧 VST® Hosting Packages

🔧 Native Infrastructure

Key Features

Flutter UI + Dart Audio Processing

Native Performance

Cross-Platform Support

Quick Start

Prerequisites

Building Your First VST® Plugin

Creating Your Own VST® Plugin

Building a VST® Host Application

Project Structure

Development Workflow

VST® Plugin Development

Parameter Binding System

Examples in Production

Flutter Reverb Plugin

Echo Plugin

Testing

Contributing

Legal Notice

License

About

Topics

Resources

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages