Codebase Architecture and Modularity Questions

Designing and organizing large codebases to be modular, maintainable, and scalable. Candidates should be able to describe how to identify component boundaries, define stable interfaces and contracts, select appropriate service boundaries versus library modules, structure packages and ownership, and enable multiple teams to build and release independently. Discussions should cover dependency management, strategies to reduce coupling, versioning and backward compatibility, testing and continuous integration practices, incremental refactoring approaches, and how to balance short term delivery with long term maintainability and technical debt reduction.