Airbnb successfully completed a large-scale code migration from Enzyme to React Testing Library (RTL) using LLMs, originally estimated to take 1.5 years, in just 6 weeks. This post outlines the automated migration pipeline, the challenges faced, and techniques used, such as file validation, retry loops, and context expansion. The migration achieved a 97% success rate, demonstrating the potential of LLMs for enhancing developer productivity and code transformation.