Building large mobile apps is hard. Keeping developers productive while working on large mobile apps is harder. Most Android developer tools target smaller apps, so how do we think about building some of the largest apps in the world? In this talk, you’ll learn how Uber enables hundreds of Android developers to contribute on a handful of app in a single monorepo, while keeping developers feeling productive and shipping reliable apps quickly. We’ll cover how the mobile teams are structured, how developer productivity is measured and monitored, custom tools like Bazel & Buck, our CI/CD diff pipeline, our testing and device lab infrastructure, our remote dev server environment, our custom IDE plugins and tools, how we modularize and use common app architecture and frameworks to keep consistency in all our apps, how we prioritize open-source engagement, and some of our best practices to continually evolve and modernize our apps at scale along to keep up with the fast moving pace of Android. Whether you're planning for your own app's scale, or just curious how it's done in one of the largest apps, you won't want to miss this talk.