Redex provides a framework for reading, writing, and analyzing .dex files, and a set of optimization passes that use this framework to improve the bytecode. An APK optimized by Redex should be smaller and faster.

Fewer bytes also means faster download times, faster install times, and lower data usage for cell users. Lastly, less bytecode also typically translates into faster runtime performance.

Redex has deep integration with Buck where your Redex config is passed as a parameter to the Buck android_binary rule when generating the APK.