Flutter Embedding CLI

A command-line tool for generating modules that allow embedding Flutter into native iOS, Android, React Native, Web (React), and Web (Angular) applications.

Screenshot

Screenshot 1

Screenshot 2

Why Flutter Embedding CLI?

Flutter's official "add-to-app" approach is notoriously complex and painful to set up. It requires manual configuration of build systems, managing framework dependencies across platforms, and writing boilerplate communication code — all of which is error-prone and time-consuming.

Flutter Embedding CLI eliminates this pain. With a single command, it generates production-ready modules for any target platform, complete with:

✅ Pre-configured build setup and dependency management
✅ Type-safe communication between Flutter and host using Protocol Buffers
✅ Ready-to-use example apps for immediate testing
✅ Proper packaging (CocoaPods for iOS, AAR for Android, npm packages for web)

Stop wrestling with build configurations. Start shipping features.

Why Protocol Buffers Instead of Pigeon?

Flutter's official Pigeon package is great for type-safe communication, but it only supports generating code for native Android and iOS platforms. This is a significant limitation when you want to embed Flutter in web applications or React Native.

Flutter Embedding CLI uses Protocol Buffers because:

Universal platform support — Proto files generate Dart code plus native code for all requested host platforms: iOS (Swift), Android (Java), React Native (TypeScript), React Web (TypeScript), and Angular Web (TypeScript). One definition, all platforms.
Built on gRPC foundations — The communication layer hooks into the gRPC serialization system. Messages are converted to bytes and sent over the platform channel (iOS/Android), the embedding channel (React Native), or JS interop (Web). This proven approach handles complex data types reliably.
Excellent backward compatibility — Protocol Buffers have well-established rules for evolving message schemas. You can add new fields, deprecate old ones, and maintain compatibility between different versions of your Flutter module and host apps.

Overview

This CLI tool helps developers create the module and example applications for integrating Flutter modules into existing native mobile and web applications. It supports the following platforms:

iOS - Native iOS framework with CocoaPods integration
Android - Android Archive (AAR) module
React Native - Cross-platform React Native module
Web (React) - React web component module
Web (Angular) - Angular web component module

The tool uses Protocol Buffers (proto files) to define type-safe communication between the host platform and Flutter, enabling seamless handover of data and method calls.

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  flutter_embedding: ^0.0.1-beta.2

dev_dependencies:
  flutter_embedding_cli: ^0.0.1-beta.2

Configuration

pubspec.yaml Requirements

Your Flutter module's pubspec.yaml must include the flutter_embedding configuration section and the standard Flutter module configuration:

flutter_embedding:
  # Required: Unique identifier for your module
  package_name: com.example.counter_module
  
  # Required: Display name for the embedding (used in generated code)
  name: CounterEmbedding
  
  # Optional: Module name (defaults to {project_name}_module)
  module_name: counter_embedding
  
  # Proto handovers configuration - defines communication between Flutter and host
  handovers:
    # Proto files defining services that Flutter can call on the host
    to_host:
      - handovers_to_host_service.proto
    # Proto files defining services that the host can call on Flutter
    to_flutter:
      - handovers_to_flutter_service.proto
    # Message type used to pass initial parameters when launching Flutter
    start_params: StartParams
  
  # Platform-specific configuration (all optional)
  ios:
    example:
      bundle_identifier: com.example.ios.app
      display_name: My iOS App
      brick_patch: embedding/example_patch_bricks/ios
  
  android:
    example:
      package_name: com.example.android.app
      brick_patch: embedding/example_patch_bricks/android
  
  react_native:
    # Optional: defaults to {module_name}-react-native
    package_name: my-react-native-module
    example:
      brick_patch: embedding/example_patch_bricks/react-native
  
  web_react:
    # Optional: defaults to {module_name}-react
    package_name: my-react-module
    example:
      brick_patch: embedding/example_patch_bricks/web-react
  
  web_angular:
    # Optional: defaults to {module_name}-angular
    package_name: my-angular-module
    example:
      brick_patch: embedding/example_patch_bricks/web-angular

flutter:
  module:
    androidX: true
    androidPackage: com.example.flutter_module
    iosBundleIdentifier: com.example.flutterModule

Proto Files for Handover Communication

Proto files define the communication contract between your Flutter module and the host platform. Place your proto files in embedding/protos/.

handovers_to_host_service.proto - Define services that Flutter can call on the host (e.g., get host info, request exit)
handovers_to_flutter_service.proto - Define services that the host can call on Flutter (e.g., change language, change theme), plus the StartParams message for initial parameters

See packages/example_module/embedding/protos/ for complete examples.

The CLI automatically generates platform-specific code from these proto files using protoc.

Usage

The CLI provides a single command with multiple subcommands:

dart run flutter_embedding_cli:generate [options] <command> [arguments]

Commands

iOS Module Generation

Generate iOS Flutter module and optionally create an example app:

dart run flutter_embedding_cli:generate ios [--example] [--verbose]

Options:

--example, -e: Generate an example iOS app alongside the module
--verbose, -v: Show verbose output

What it does:

Generates a Flutter module plugin with Swift handover services from proto files
Builds the Flutter iOS framework with CocoaPods support
Generates ZIP files of the iOS SDK
Creates Podspec files for CocoaPods integration
Generates a Pod helper file
If --example is specified, creates a complete example iOS app

Android Module Generation

Generate Android Flutter module and optionally create an example app:

dart run flutter_embedding_cli:generate android [--example] [--verbose]

Options:

--example, -e: Generate an example Android app alongside the module
--verbose, -v: Show verbose output

What it does:

Generates a Flutter module plugin with Java handover services from proto files
Builds the Flutter Android Archive (AAR)
If --example is specified, creates a complete example Android app

React Native Module Generation

Generate React Native Flutter module and optionally create an example app:

dart run flutter_embedding_cli:generate react-native [--example] [--verbose]

Options:

--example, -e: Generate an example React Native app alongside the module
--verbose, -v: Show verbose output

What it does:

Generates the React Native module structure with TypeScript handover services
Builds both Android AAR and iOS framework
Copies Flutter artifacts to the appropriate platform directories
Generates ZIP files and Podspecs for iOS
Runs npm install, ci, and pack commands (packaging the module)
If --example is specified, creates a complete example React Native app

Web React Module Generation

Generate a React web module and optionally create an example app:

dart run flutter_embedding_cli:generate web-react [--example] [--verbose]

Options:

--example, -e: Generate an example React web app alongside the module
--verbose, -v: Show verbose output

What it does:

Generates the React web module structure with TypeScript handover services
Builds Flutter for web with source maps
Runs npm install, ci, build, and pack commands
If --example is specified, creates a complete example React web app

Web Angular Module Generation

Generate an Angular web module and optionally create an example app:

dart run flutter_embedding_cli:generate web-angular [--example] [--verbose]

Options:

--example, -e: Generate an example Angular web app alongside the module
--verbose, -v: Show verbose output

What it does:

Generates the Angular web module structure with TypeScript handover services
Builds Flutter for web with source maps
Runs npm install, build, and pack commands
If --example is specified, creates a complete example Angular web app

Multiple Views (Web Only)

Web platforms (React and Angular) support multiple Flutter views within the same application. This allows you to:

Dynamically add and remove Flutter views at runtime
Run multiple independent Flutter instances side by side
Each view has its own handover service client for independent communication

The Flutter engine is initialized once with multiViewEnabled: true, and each FlutterEmbeddingView component manages its own view instance. Views can be added and removed dynamically while sharing the same Flutter engine.

Output Structure

All generated artifacts are placed in the embedding/ directory:

Flutter Module Plugin

embedding/{module_name}/ - Generated Flutter plugin with handover services

iOS

embedding/ios/sdk/ - iOS framework and CocoaPods files
embedding/ios/example/ - Example iOS app (if --example flag used)

Android

embedding/android/sdk/ - Android AAR files
embedding/android/example/ - Example Android app (if --example flag used)

React Native

embedding/react-native/module/ - React Native module package
embedding/react-native/example/ - Example React Native app (if --example flag used)

Web React

embedding/web-react/module/ - React web module package
embedding/web-react/example/ - Example React web app (if --example flag used)

Web Angular

embedding/web-angular/module/ - Angular web module package
embedding/web-angular/example/ - Example Angular web app (if --example flag used)

Patch Bricks

You can customize the generated example apps using Mason patch bricks. Specify the path to your custom brick in the flutter_embedding configuration:

flutter_embedding:
  ios:
    example:
      brick_patch: embedding/example_patch_bricks/ios
  android:
    example:
      brick_patch: embedding/example_patch_bricks/android

The patch brick will be applied after the base example app is generated, allowing you to add custom code or modify generated files.

Prerequisites

Flutter SDK
For iOS: Xcode and CocoaPods
For Android: Android SDK
For React Native: Node.js and npm
For Web: Node.js and npm
Protocol Buffers compiler (protoc) with language-specific plugins:
- Dart: protoc-gen-dart
- Java: protoc-gen-grpc-java
- Swift: protoc-gen-swift and protoc-gen-grpc-swift-2
- TypeScript: protoc-gen-ts

License

MIT License

Flutter Embedding CLI

Screenshot

Why Flutter Embedding CLI?

Why Protocol Buffers Instead of Pigeon?

Overview

Installation

Configuration

pubspec.yaml Requirements

Proto Files for Handover Communication

Usage

Commands

iOS Module Generation

Android Module Generation

React Native Module Generation

Web React Module Generation

Web Angular Module Generation

Multiple Views (Web Only)

Output Structure

Flutter Module Plugin

iOS

Android

React Native

Web React

Web Angular

Patch Bricks

Prerequisites

License

Libraries

flutter_embedding_cli package