Kotlin at Trello: Mobile Development Best Practices
Article Summary
Vishnu Rajeevan from Trello shares how his team went from 0% to 30.8% Kotlin in just over a year. Their strategy? Start with tests, then make every new feature Kotlin-only.
Trello's Android team adopted Kotlin in October 2016, right after version 1.0.4 launched. This post documents their journey from cautious experimentation to full commitment, including the team mandate that drove adoption: all new features in Kotlin, and any old feature updates must be converted first.
Key Takeaways
- Started with tests as low-risk entry point before building production features
- Grew from 15% to 30.8% Kotlin in six months with aggressive adoption
- Team rule: convert old features to Kotlin before making any updates
- Compile speeds improved, Kotlin no longer causes major build slowdowns
Critical Insight
Trello successfully scaled Kotlin adoption to nearly one-third of their codebase by starting small with tests, then enforcing Kotlin-first rules for all new work.
