gradle-build-performance

Start by generating a Build Scan with ./gradlew assembleDebug --scan to identify the slow phase. Then enable configuration cache, build cache, and parallel execution in gradle.properties, applying one optimization at a time and measuring after each change.

Replace kapt dependency declarations with ksp equivalents for supported libraries like Hilt, Room, and Moshi, and swap the kotlin-kapt plugin for com.google.devtools.ksp. KSP runs roughly twice as fast as kapt and is mandatory for AGP 9 compatibility.

The configuration cache skips the configuration phase on subsequent builds when inputs have not changed, available in AGP 8.0+. Enable it with org.gradle.configuration-cache=true, starting with problems=warn before moving to fail mode.

Cache misses typically result from non-deterministic task inputs, dynamic dependency versions, or the build cache not being enabled. Set org.gradle.caching=true, pin exact dependency versions, and audit tasks for unstable inputs like timestamps.

No, org.jetbrains.kotlin.kapt is incompatible with AGP 9's built-in Kotlin support. Migrate to KSP 2.3.1 or later, or use the com.android.legacy-kapt plugin as a transitional fallback for processors without KSP equivalents.

Slow configuration usually comes from eager task creation with tasks.create, file or network I/O during configuration, or subprojects/allprojects blocks. Use tasks.register, defer I/O with providers, and replace subproject blocks with convention plugins.