When our e-learning Flutter app grew to 50+ modules, the hardest part was not how to keep "each module independent," but rather how they "talked to each other." A codebase with 50+ modules and 25 engineers, split into 3 teams and simultaneously working on it, started to cause: - Conflict issues in code and dependencies. - Importing multiple other packages into a new feature module. - A refactor in the profile module broke all the other modules. - Code review challenges across multiple modules. This talk covers our migration to an event-driven architecture to solve the above problems and the learnings along the way.