Why we think Flutter will help us scale mobile development at Nubank (Detailed PDF Report
Article Summary
Nubank evaluated Flutter, React Native, and Kotlin Native across 11 criteria to solve a critical scaling problem. Here's how they decided.
In 2019, Nubank's Mobile Architecture Task Force ran a rigorous R&D project to pick one cross-platform framework. They tested production features, ran usability studies with engineers, and analyzed everything from developer experience to long-term viability.
Key Takeaways
- Flutter won on developer experience: built-in hot reload, testing tools, and stable APIs
- React Native had the largest community but 32 dependencies vs Flutter's 3
- Kotlin Native required building all UI abstractions from scratch (10x cost estimate)
- User tests showed novice developers were more productive in Flutter after first contact
- Team prioritized people impact over technical specs to reduce engineer anxiety
Nubank chose Flutter as their main mobile platform based on superior testing infrastructure, lower maintenance risk, and better scalability for autonomous product teams.
About This Article
Nubank's mobile teams worked across three separate tech stacks: native iOS with Swift, native Android with Kotlin, and React Native. This fragmentation created knowledge silos and made it hard for developers to share expertise or onboard new people.
The Mobile Architecture Task Force built an 11-criterion evaluation framework to compare Flutter, React Native, and Kotlin Native. They tested it with both junior and senior engineers, reviewed over 1,000 pull requests from each platform, and ran catastrophic scenario role-plays to see how each would handle real problems.
Flutter won the evaluation. It had 3 production dependencies compared to React Native's 32, zero breaking changes since version 1.0.0, and better built-in testing tools for unit, integration, and end-to-end tests without needing a renderer. Nubank standardized on Flutter across the company.