Layered Architecture

Layered monorepo architecture for Flutter apps — four layers organized as independent Dart packages with strict unidirectional dependencies.

Core Standards

Apply these standards to ALL layered architecture work:

• Four layers — Data, Repository, Business Logic, Presentation — every feature spans exactly these four layers
• Unidirectional dependencies — Presentation → Business Logic → Repository → Data — never skip or invert a layer
• Data and Repository layers live in packages/ — each is an independent Dart package with its own pubspec.yaml
• Business Logic and Presentation live in lib/ — organized by feature within the app
• Data layer packages contain zero domain/business logic — they must be reusable in unrelated projects
• No inter-repository dependencies — repositories never import other repositories
• No Flutter SDK in data or repository packages — scaffold with the very_good_cli MCP server create dart_package tool
• One repository per domain — user_repository, weather_repository, auth_repository
• Path dependencies for local packages — never git: or pub version references for packages in the same repo