Whop, an online marketplace for digital products, transformed their platform by migrating from Ruby on Rails to Next.js and then adopting App Router for improved page speed and developer experience. The company achieved significant improvements in their Real Experience Score, percentage of Good URLs, and Core Web Vitals, showcasing the power of modern web development tools like Next.js and App Router. Whop's commitment to speed, scalability, and developer experience has paid off with impressive performance gains and a more streamlined development process.