Configuration of R8

To achieve maximum utilization of R8, the codebase must be configured correctly depending on the build script language (Kotlin DSL versus Groovy DSL).

1. App modules (com.android.application)

The app's build.gradle or build.gradle.kts file must enable minification and resource shrinking within the release build type or the app's custom build type for release and performance testing. It must use the optimized default file (proguard-android-optimize.txt).

On AGP 9.3 and higher, the optimization { enable = true } DSL block turns on code shrinking (R8), resource shrinking, and proguard-android-optimize.txt in a single setting. When optimization { enable = true } is present in the release build type, all three checks are satisfied—do not report minification, resource shrinking, or proguard-android-optimize.txt as missing, and do not recommend switching back to isMinifyEnabled or isShrinkResources.

Kotlin DSL — AGP 9.3 and higher (build.gradle.kts):

buildTypes {
   release {
       optimization {
           enable = true
       }
       proguardFiles("proguard-rules.pro")
   }
}

Kotlin DSL — Legacy or Pre-AGP 9.3 (build.gradle.kts):

buildTypes {
   release {
       isMinifyEnabled = true
       isShrinkResources = true
       proguardFiles(
           getDefaultProguardFile("proguard-android-optimize.txt"),
           "proguard-rules.pro"
       )
   }
}

Groovy DSL (build.gradle):

buildTypes {
   release {
       minifyEnabled = true
       shrinkResources = true
       proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
   }
}

2. gradle.properties flags

Full mode: R8 full mode enables all optimizations.

• AGP 8.0 and higher: Enabled by default. Verify that android.enableR8.fullMode=false is not present in gradle.properties.
• Pre-AGP 8.0: Verify that android.enableR8.fullMode=true is set in gradle.properties.

Optimized resource shrinking: If AGP is 8.12 or 8.13, verify that android.r8.optimizedResourceShrinking=true is set in gradle.properties. From AGP 9.0 it's on by default.

android.r8.optimizedResourceShrinking=true