Erik Kerber

Perhaps you—or a mobile developer you know—has occasionally complained about “slow builds.” And maybe you’ve wondered: Would another build system solve the problem? In January 2024, after reading yet another batch of “faster build speed, please!” requests in our quarterly developer experience survey, the Slack Android Developer Experience team decided it was time for bold action. With Gradle sometimes spending as long as 10 minutes in the configuration stage of our ~1000-module project, we chose to evaluate an alternative designed for large, modularized codebases: Bazel. Over the course of the following year, we had made significant progress—building the app, running all tests, and achieving ~70% faster test result times in CI. However, our effort to finalize the project by integrating Bazel into the local development toolchain ran into considerable friction. Ultimately, with shifting priorities, we decided to put the project on hold. In this session, we’ll share our experience with Bazel on Android: •Why we chose this path •How we approached the evaluation •Performance comparisons •Lessons learned •Our impression of the state of Android support in Bazel Advanced knowledge of Gradle or Bazel is not required, though this talk will be most interesting to those familiar with the Android tooling and build systems problem space.