Android • Android App Development • Kotlin

How I Cut My Gradle Build Time by 50%

By James Cullimore • • 8 min read
How I Cut My Gradle Build Time by 50%

Android developers are no strangers to the occasional long build time. As projects grow in complexity, waiting on Gradle to finish its work can quickly become a frustrating and productivity-draining experience. While Kotlin DSL brings modern syntax and type safety to build scripts, it can also introduce subtle performance costs compared to its older Groovy counterpart.

In this article, we explore practical strategies to improve Gradle build performance in Android projects using Kotlin. We’ll examine useful gradle.properties configurations, discuss how upgrading Gradle, Kotlin, and Java versions can make a tangible difference, and take a closer look at the trade-offs between Groovy and Kotlin build scripts—yes, Groovy still has a slight edge when it comes to speed.

Whether you’re optimizing a large-scale app or simply looking to tighten your feedback loop during development, these insights can help you streamline your build process and make your development experience a bit smoother. Let’s dive in and see what makes Gradle run just a little faster.

Create Benchmarks

Before jumping into any changes, it’s a good idea to establish a clear baseline. Make sure to run a few benchmarks on your current setup so you can accurately measure the impact of each tweak. Track both clean builds (after clearing the Gradle cache) and incremental builds to get a complete picture. And don’t just run each build once — run them multiple times if possible. Things like background processes, indexing, and even your laptop’s thermal state can influence results more than you’d expect. Jot down your observations as you go. It might feel a bit tedious, but it’ll help you make informed decisions rather than relying on guesswork.

If the embedded code does not load, open it on GitHub Gist.

You can customize columns depending on how deep you want to go (e.g. add RAM usage, CPU %, or specific machine specs if you’re being extra thorough).

Update Everything

Before tweaking properties or switching DSLs, make sure you’re working with the latest stable versions of your tools. Gradle, Kotlin, the Android Gradle Plugin (AGP), and even Java itself all receive regular updates that include not just new features, but meaningful performance improvements under the hood.

At the time of writing, here are some versions worth targeting:

  • Java: 23 (yes, it’s stable!)
  • Kotlin: 2.1
  • AGP: Latest stable (check here for updates)
  • Gradle: Whatever’s latest and stable from gradle.org/releases

Updating these components can significantly reduce build times on their own. Be sure to re-run your benchmarks after each version bump to see the impact. Sometimes even a minor patch version can shave off a few precious seconds.

Oh, and don’t forget to check your IDE version too — Android Studio updates often bring better build caching and indexing performance, which can quietly improve your workflow without you realizing it.

Optimize gradle.properties

gradle.properties

One of the most straightforward ways to boost Gradle’s performance is by optimizing your gradle.properties file. Below are some important properties that can make a difference, as well as a few extra ones that you might find helpful for speeding things up.

JVM Memory Settings

org.gradle.jvmargs=-Xmx4g -XX:+HeapDumpOnOutOfMemoryError -XX:+UseParallelGC -XX:MaxMetaspaceSize=512m -Dkotlin.daemon.jvm.options=-XX:MaxMetaspaceSize=1g -Dlint.nullness.ignore-deprecated=true
  • -Xmx4g: Sets the maximum heap size for the JVM to 4 GB. This helps Gradle and the Kotlin compiler manage memory more efficiently, especially for larger projects.
  • -XX:+HeapDumpOnOutOfMemoryError: This option ensures that if Gradle runs out of memory, it will create a heap dump to help you diagnose the issue.
  • -XX:+UseParallelGC: Enables parallel garbage collection, which can help with memory management and reduce pauses during the build.
  • -XX:MaxMetaspaceSize=512m: Limits the size of the metaspace (used for class metadata) to 512 MB. This prevents the JVM from consuming too much memory in certain situations.
  • -Dkotlin.daemon.jvm.options=-XX:MaxMetaspaceSize=1g: Instructs the Kotlin daemon to use up to 1 GB for its metaspace, which can help with Kotlin compilation tasks.
  • -Dlint.nullness.ignore-deprecated=true: Disables warnings for deprecated nullness annotations. This can reduce lint time slightly if you’re not concerned with these warnings.

Enable Gradle Caching

org.gradle.caching=true

Gradle’s build cache allows Gradle to store build outputs, so it doesn’t have to rebuild everything from scratch every time. When enabled, Gradle reuses tasks and results from previous builds, which can drastically improve build times, especially in larger projects.

Parallel Build Execution

org.gradle.parallel=true

This property enables parallel execution of independent tasks. It’s most beneficial for multi-module projects, where tasks in different modules can run simultaneously. Note: It should be used with decoupled projects — those that have minimal interdependencies. For tightly coupled projects, this could cause issues.

Configure on Demand

org.gradle.configureondemand=true

For multi-module projects, this tells Gradle to only configure the projects that are necessary for the current build. This reduces the configuration overhead when only a subset of modules needs to be built, improving speed for large projects.

Maximize Gradle Daemon Use

org.gradle.daemon=true

By enabling the Gradle daemon, you keep the process running between builds, avoiding the startup time required for each build. It can dramatically reduce build times, especially for incremental builds. Gradle will automatically manage the daemon’s lifecycle, so no extra configuration is needed beyond this property.

Keep the Build Log Clean

org.gradle.logging.level=info

Setting the logging level to info ensures that Gradle only logs essential information during the build. This can reduce the time it spends processing verbose logs, helping the build process complete faster. You can adjust the level to quiet if you want minimal output.

Optimize Dependency Resolution

Dependency resolution can often be a hidden bottleneck in build performance. Gradle needs to resolve and download dependencies from remote repositories, and this process can take time — especially if you’re working with a lot of third-party libraries. Here are some key strategies to optimize how Gradle handles dependencies:

Avoid Unnecessary and Unused Dependencies

Managing third-party libraries and their transitive dependencies is essential, but it can also introduce unnecessary overhead. Unused dependencies can pile up over time, especially during refactors, and they add both maintenance cost and longer build times.

Best practices:

  • Remove unused dependencies: If a third-party library is no longer used in your project, make sure it’s removed from the dependency list. You can use tools like the Gradle Lint Plugin to identify and clean up unused dependencies.
  • Limit unnecessary dependencies: Avoid pulling in entire libraries if only a few methods or classes are needed. If possible, consider:
  • Implementing the required functionality yourself.
  • Copying the necessary code from the library (with proper attribution, of course), especially if it’s open source.

Optimize Repository Order

Gradle resolves dependencies by searching through the repositories in the order they are declared. If you have multiple repositories, Gradle will search through them one by one, potentially increasing the number of network requests.

Best practice:

  • Prioritize repositories: Always declare the repository that hosts the largest number of your dependencies first in the repositories block. This minimizes the number of requests Gradle needs to make to resolve dependencies.
repositories {
    mavenCentral()   // Most dependencies go here, so put it first
    google()         // Second, as Android-related dependencies often live here
    maven { url = uri("https://my.custom.repo") }  // Custom repositories last
}

Minimize Repository Count

The more repositories you declare, the longer it takes for Gradle to search through them. By reducing the number of repositories, you reduce the overhead.

Best practice:

  • Limit repositories: Only include the necessary repositories for your project. If you’re using custom repositories, consider creating a virtual repository that aggregates multiple repositories into one. Then, just add that virtual repository to your build file.

This minimizes the number of network calls Gradle has to make.

Minimize Dynamic and Snapshot Versions

Dynamic versions (e.g., "2.+" or "latest.integration") and snapshots force Gradle to check remote repositories every time you build to fetch newer versions. This can slow things down, as Gradle has to constantly verify if new versions are available.

Best practice:

  • Avoid dynamic versions: If possible, specify a fixed version for each dependency. If you must use dynamic versions, you can control how often Gradle checks for updates using these settings:
# Cache dynamic versions for 24 hours (default)
org.gradle.cache.dynamicVersionsFor=24h
# Cache changing modules for 48 hours
org.gradle.cache.changingModulesFor=48h

Why this matters: With dynamic versions, Gradle will query the repository more frequently. If you don’t need the absolute latest release every time, it’s better to remove custom settings or limit their frequency.

5. Find Dynamic Versions Using Build Scans

If you suspect dynamic versions are slowing down your builds but aren’t sure where they’re being used, Gradle Build Scans can help identify them.

How to use: Run a build scan and search for any dependencies that use dynamic versions. Build scans provide a visual representation of your build process and highlight issues like this.

gradle build --scan

Once the scan is complete, visit the link provided to analyze your build. You’ll be able to pinpoint which dependencies are using dynamic or snapshot versions.

Groovy vs. Kotlin DSL: A Speed Trade-Off

When it comes to build scripts, Groovy still has a slight edge in terms of performance over Kotlin DSL. While Kotlin is type-safe, offers IDE support, and has better tooling for refactoring, Groovy tends to execute a little faster for Gradle builds due to its simpler, dynamically typed nature.

That said, Kotlin is ideal for larger projects where safety, clarity, and maintainability are more important than raw execution speed. If you’re working on a smaller project or need to squeeze out every last second of build time, sticking with Groovy might give you a slight advantage. But for most Android projects, the benefits of Kotlin DSL — such as better error checking, IDE support, and autocompletion — outweigh the minor performance cost.

So, while Groovy is faster, Kotlin DSL is perfect for those who prioritize long-term code quality and tooling.

Conclusion

Optimizing Gradle build times may seem like a daunting task, but as we’ve seen, making small, targeted adjustments can lead to significant improvements. Whether it’s tweaking your gradle.properties, updating dependencies, or configuring parallel execution, each step can add up to a faster, smoother development experience.

In fact, on a recent project, I was able to cut my Gradle build times by a massive 50%, reducing the build time from 9 minutes to just 4:30. How? By adding a few key optimizations to my gradle.properties file:

org.gradle.jvmargs=-Xmx4g -XX:+HeapDumpOnOutOfMemoryError -XX:+UseParallelGC -XX:MaxMetaspaceSize=512m -Dkotlin.daemon.jvm.options=-XX:MaxMetaspaceSize=1g -Dlint.nullness.ignore-deprecated=true
org.gradle.caching=true
org.gradle.parallel=true
org.gradle.configureondemand=true

These settings helped me make the most out of Gradle’s powerful caching, parallelism, and JVM configuration features, all of which contributed to significant performance gains.

If you’re looking for more ideas on how to improve your build performance, be sure to check out this excellent project, Pokedex, which showcases some modern Android development practices and performance optimization strategies. It’s a fantastic reference for anyone wanting to level up their Android builds.

For even more advanced tips and options, don’t forget to visit the official Gradle Performance Guide here.

By combining the tips in this article with some of the tools and settings we’ve discussed, you’ll be well on your way to faster builds and more efficient development cycles. Remember, every project is different, so don’t be afraid to experiment and see what works best for your own setup!