Modularizing Our Driver App for Android: Benefits & Way Ahead (Part-3)

Gojek's driver app modularization cut CI build times by 33% and unlocked team-level productivity metrics. Here's what they learned from breaking up their monolith.

This is Part 3 of Gojek's series on modularizing their Android driver app. After extracting core modules, utilities, and features, the team measured the real-world impact on build speeds, code quality, and team productivity.

Key Takeaways

• CI build times dropped from 30 minutes to just over 20 minutes
• Reduced app module classes from 78% to 68% of total codebase
• Clear feature ownership enabled per-team metrics: test coverage, binary size, crashes
• Separate API and implementation modules let teams experiment with different architectures
• Manual code reviews still essential to prevent core modules becoming dumping grounds

The team shares why identifying inputs and outputs for each feature was the key to unlocking architectural freedom across different parts of the app.