Removing 30% of our iOS crashes

Robinhood eliminated 30% of ALL iOS crashes by refactoring a single screen. That screen drove 30% of their revenue at the time.

The Robinhood iOS team rebuilt their Option Chain screen from scratch, migrating from a 5-year-old UIViewController to their modern NAPA architecture and Titan data framework. This critical screen handles real-time options trading data for 65% of their options customers.

Key Takeaways

• Migrated from NSFetchedResultsController to NAPA and Titan frameworks
• Reduced codebase by 30% while improving modularity and testability
• Made switching between calls/puts 200% faster, expiration dates 37% faster
• Used 28 snapshot test variations to prevent UI regressions
• Built custom UIScheduler to optimize RxSwift performance during scrolling

Their custom RxSwift scheduler trick for smooth scrolling with multiple observers per cell is worth the read alone.