Google highlights Reddit case study to push wider adoption of R8 app optimization tool

Google is placing renewed emphasis on the R8 optimization tool in Android development, using a case study involving Reddit’s Android app to show the performance impact that can result from enabling full optimization settings. The company published a blog post outlining how R8 can reduce app size, improve startup speed, and cut down on performance-related issues, while also providing updated documentation to guide developers through adoption.

According to Google, Reddit ran performance evaluations using internal metrics and Android Vitals, then enabled R8 optimizations across the app. Following the rollout, Reddit reported measurable improvements, including faster cold startup, lower instances of “Application Not Responding” errors, and reduced app size. The company also cited improved frame rendering. Google presented the example as an illustration of how performance changes translate to user sentiment and store ratings.

Google also shared that Reddit engineers conducted controlled benchmarking using Jetpack Macrobenchmark, comparing an unoptimized version of the app against a build using R8 along with Baseline Profiles and Startup Profiles. The tests indicated notable differences in launch times, rendering stability, and Just-in-Time compilation activity.

While the case study focused on Reddit, Google framed the performance spotlight as part of a broader push for developers to enable R8’s full mode. The updated guidance includes configuration instructions, clarification on keep rules to prevent incorrect code removal, and reminders to replace legacy ProGuard settings. The company also noted that some apps still rely on configuration files that disable optimization.

Google additionally referenced another example from Disney+, where removing a legacy flag and switching to an optimized configuration file led to improved app startup and fewer user-reported freezes.