How Tinder Decomposed Its iOS Monolith App Handling 70M Users

Tinder successfully decomposed its massive iOS monolith serving 70M users by using compiler-driven dependency analysis to create a modular architecture. The team built automated tools that extracted the dependency graph from Swift compiler data, then systematically moved files in phases starting with leaf nodes. This approach reduced build times by 78% and completed the migration in 6 months instead of an estimated 12 years, all without causing production incidents. The process involved updating dependencies, imports, access controls, and dependency injection patterns for each moved file.