Flutter › Flutter App Architecture with Modular Feature Folders

How can a large Flutter application be split into genuinely separate internal packages, one for each major feature, using a monorepo approach, rather than simply keeping everything within just folders inside a single unified app?

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Answer

For a genuinely very large Flutter application, particularly one being developed by several separate independent teams, splitting major features into their own entirely separate internal Dart packages within a monorepo, meaning one single shared repository containing several genuinely distinct packages, enforces considerably stronger boundaries between features compared to simply using folders alone, since a package's own public interface deliberately controls exactly what other features are actually permitted to depend on and directly access, and tools such as Melos specifically help manage versioning, dependencies, and running commands consistently across this kind of genuinely more complex multi package repository structure.
packages/
  checkout_feature/
  profile_feature/
  shared_ui/
apps/
  main_app/
Real-world example A large company with several genuinely separate teams splits their sprawling Flutter app into distinct internal packages for checkout, profile, and shared UI components, using Melos to properly manage the increased complexity of consistently versioning and testing each of those individual packages together.

Common follow-ups: What is Melos, and how specifically does it help manage a genuinely complex Dart monorepo?;At what specific point does the added structural overhead of separate packages genuinely become worthwhile compared to simply using folders alone?