Duolingo: continuous integration on Amazon EC2 Mac

In this episode of the AWS Developers Podcast, we explore how Duolingo—the app with 100 million monthly active users—optimized its CI/CD infrastructure to handle builds for 300 pull requests every week. Sharanya Viswanath and Murtaza Javaid explain how their platform engineering team reduced build times from 50 minutes to just 16 minutes by migrating to Amazon EC2 Mac and implementing advanced autoscaling and caching strategies. We also discuss the importance of modularization, macOS and Xcode version management, and automation with Fastlane to make the process more robust and efficient. An interesting discussion on the technical challenges and solutions put in place to ensure resilience and stability for iOS builds at scale.