Home / modularization iOS interview question
Architecture
Modularization iOS interview question
Modularization is a staff-level topic because it is about organizational scale and build health, not just code structure. Interviewers want to see you weigh cost against benefit.
Why and how to modularize
Splitting a monolith into modules, typically Swift packages, creates clear boundaries and ownership, enforces dependency direction, improves incremental build and test times, and lets teams work in parallel with less merge friction. Feature modules depend on shared foundation modules, and a thin app target wires them together.
The trade-offs
Be candid about cost: modularization adds boilerplate, dependency management, and up-front migration effort, and over-splitting creates its own friction. Explain sequencing a migration, extracting stable shared code first, defining interfaces between features, and avoiding cyclic dependencies. Framing it as a boundaries-and-ownership decision with real cost is the staff signal.
Go deeper than a summary
Share Your Screen works topics like this through in full: 75 solved Swift problems with tests, 9 real case studies, and 7 annotated mock interviews, so you rehearse the live round instead of just reading about it.
Frequently asked
Why modularize an iOS app?
To create clear ownership boundaries, enforce dependency direction, cut build and test times, and let teams work in parallel with fewer conflicts.
What are the downsides of modularization?
Up-front migration effort, dependency-management overhead, and the risk of over-splitting, which adds friction. It pays off mainly at larger scale.