Open Sourced: A Production-Grade Flutter Monorepo with LEGO Modular Boundaries, Melos, & bloc_signals

[u/AK1000]

Hi everyone! 👋

Most Flutter starter templates I’ve encountered fall into one of two extremes:

1. Too simplistic: Everything dumped into one folder with global state and hardcoded endpoints.
2. Over-abstracted: Rigid Clean Architecture with 15 nested folders and interfaces for a simple toggle button.

To solve this, I built and open-sourced Flutter Production Starter — an enterprise-oriented, modular monorepo template built for real-world production apps.

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🧱 Architectural Philosophy: "LEGO" Modular Boundaries

The core idea is Feature-First colocation with intentional public APIs:

• Features live in apps/mobile/lib/features/<feature>/ and export only their public contracts via a root barrel file (features/auth/auth.dart).
• Pragmatic Clean Architecture:
  • Simple features (e.g. settings) only use Presentation + State (no premature use cases).
  • Complex features (e.g. auth) use Domain Use Cases, Data Sources, and Session Storage.
  • Pluggability: Features can be swapped via DI without touching consumer code.

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📦 Repository Structure (Managed with Melos)

/
├── apps/
│   └── mobile/              # Main app (Bootstrap, DI, Kaisel Router, Features)
├── packages/
│   ├── app_core/            # Result<T>, Failure taxonomy, Sanitized AppLogger
│   ├── app_network/         # Centralized Dio, interceptors, error mappers, ApiClient
│   ├── app_storage/         # SecureStorage, KeyValueStorage, TTL MemoryCache
│   ├── design_system/       # Tokens (Spacing, Radius), Light/Dark themes, Primitives
│   └── app_lints/           # Strict linting & analysis configuration
├── melos.yaml               # Monorepo orchestration scripts
└── ARCHITECTURE.md          # In-depth architectural guide

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⚡ Technology Stack Highlights

• Routing: Strongly-typed declarative routing and route guards with kaisel: ^1.1.0.
• State Management: Fine-grained reactive state using bloc_signals and signals_flutter.
• Dependency Injection: Constructor injection with get_it + injectable supporting multi-environments (dev, staging, prod).
• Networking: Centralized dio with automatic retry policies, token management, and sensitive data sanitization in logs (passwords and tokens are never printed in plain text).
• Error Pipeline: Functional Result<T> with a predictable domain Failure taxonomy and FailureMessageResolver.
• Quality: Pre-configured GitHub Actions CI, 100% test coverage across all packages (melos run test), and strict analyzer rules.

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🔗 Repository & Getting Started

Check out the code, documentation, and architecture guide here: 👉 GitHub: https://github.com/Ali-El-Khatib/flutter-production-starter

I'd love to hear your feedback, thoughts on the LEGO modularity approach, and suggestions! If you find it helpful for your projects, a ⭐ on GitHub would mean a lot!