Discover strategies for safely migrating large-scale applications to React in this conference talk by Jamis Charles from PayPal. Learn how to balance the excitement of adopting React with the critical need to maintain stability for millions of paying users. Explore practical approaches to gradual migration, optimizing for future changes, and overcoming challenges in complex legacy systems. Gain insights into PayPal's journey, including lessons learned from their Send Money feature migration, the importance of sustainable momentum, and techniques for simplifying abstraction layers. Understand the benefits of a framework-agnostic approach, the role of utility functions, and how to implement a modern stack while preserving application integrity. Perfect for developers and team leads looking to modernize their applications without compromising user experience or system reliability.