Building Android is notoriously slow and resource-hungry. Even on high-end hardware, a full AOSP build can take hours, and each release continues to grow by ~10–20%, amplifying compile times and storage pressure. For anyone maintaining custom ROMs, vendor trees, or downstream forks, faster builds are not just nice to have: regulation requiring shipping fixes faster makes build performance a core productivity issue.

Over the years, the Android ecosystem has tried to keep pace with this growing complexity. Solutions like ccache and distributed build systems (goma, reclient), and even experiments with Bazel have all aimed to make builds faster and more scalable. But these tools were designed for other projects and struggle with Android’s unique challenges — lack of sandboxing, incomplete dependency tracking, and heterogeneous toolchains.

This talk explains how the Android build system actually works, why incremental builds so often fall apart, and where the time really goes. We’ll then walk through the major open-source acceleration approaches, their strengths and limitations, and what it takes to run them effectively in your own infrastructure—whether you’re a hobbyist with a homelab or maintaining a large downstream tree.