Difference between Groovy and Kotlin DSL

Android: Difference Between Groovy and Kotlin DSL in Gradle

When you create a new Android project today, Android Studio often asks if you want to use Groovy or Kotlin DSL for your Gradle build scripts. Both options work, both generate the same APK, and both configure Gradle in the end. The real difference is in the language and developer experience you get while writing and maintaining your build.gradle files.

This guide explains what Groovy DSL and Kotlin DSL are, how they differ in Android projects, their pros and cons, and how to choose the right one for your team.

What Are Groovy DSL and Kotlin DSL in Gradle?

Gradle is the build system used by Android Studio. It reads configuration files (build scripts) that tell it how to compile code, apply plugins, manage dependencies, and generate APKs or AABs.

There are two main ways to write these build scripts:

• Groovy DSL – Traditional, file extensions build.gradle (or build.gradle Groovy).
• Kotlin DSL – Newer, file extensions build.gradle.kts (the .kts stands for “Kotlin script”).

Functionally they do the same job: configure Gradle. The difference is that one uses the Groovy language (dynamic, flexible) and the other uses the Kotlin language (statically typed, more strict and IDE-friendly).

Quick Visual Example: Groovy vs Kotlin DSL

Here is a typical Android module build script in both styles to make the difference easier to see.

Groovy DSL (build.gradle)

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    namespace 'com.example.app'
    compileSdk 34

    defaultConfig {
        applicationId "com.example.app"
        minSdk 24
        targetSdk 34
        versionCode 1
        versionName "1.0"
    }

    buildTypes {
        release {
            minifyEnabled false
        }
    }
}

dependencies {
    implementation "androidx.core:core-ktx:1.13.1"
    implementation "androidx.appcompat:appcompat:1.7.0"
}
  

Kotlin DSL (build.gradle.kts)

plugins {
    id("com.android.application")
    id("org.jetbrains.kotlin.android")
}

android {
    namespace = "com.example.app"
    compileSdk = 34

    defaultConfig {
        applicationId = "com.example.app"
        minSdk = 24
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"
    }

    buildTypes {
        getByName("release") {
            isMinifyEnabled = false
        }
    }
}

dependencies {
    implementation("androidx.core:core-ktx:1.13.1")
    implementation("androidx.appcompat:appcompat:1.7.0")
}
  

The structure is the same, but the syntax is slightly different. Kotlin DSL uses quotes in id("..."), assignment with =, and type-safe accessors like isMinifyEnabled instead of minifyEnabled.

Core Difference: Language and Typing

The most important difference between Groovy DSL and Kotlin DSL is the underlying language:

• Groovy DSL is based on Groovy, a dynamically typed language. Types are resolved mostly at runtime.
• Kotlin DSL is based on Kotlin, a statically typed language. Types are known at compile time.

This has major impacts on how you write Gradle scripts:

• With Groovy DSL, you can often write shorter, more flexible code, but mistakes like typos or wrong types may only show up at build time (or even runtime in some APIs).
• With Kotlin DSL, you getstrong type safety, better auto-completion, and compile-time checks directly in Android Studio, at the cost of slightly more explicit syntax.

IDE Support and Developer Experience

One of the main reasons many Android developers move to Kotlin DSL is the IDE support. Because Kotlin is statically typed and first-class in Android Studio, the editor can understand your build scripts much better.

With Kotlin DSL, you typically get:

• Better auto-completion for Gradle APIs, plugin options, and dependencies.
• Stronger refactoring support (rename, find usages, navigation) in build scripts.
• Earlier error detection when you use the wrong property or type.

Groovy DSL is also supported, and Gradle has used Groovy for years, but because Groovy is dynamic, some errors are only discovered during execution. Code completion can be less reliable because the IDE cannot always know the exact type behind a DSL block.

Performance and Build Reliability

Both DSLs ultimately drive the same Gradle engine and produce the same build outputs. However, Kotlin’s static typing can help you catch configuration errors earlier and avoid surprising runtime failures in your build scripts.

In general:

• Kotlin DSL shines in larger, long-lived projects where maintainability, readability, and reliability matter a lot.
• Groovy DSL can still be perfectly fine for smaller projects, rapid prototyping, or teams with strong Groovy/Gradle experience.

Build speed differences are usually small compared to what your actual code and dependencies do, but many teams report that once they get used to Kotlin DSL, they write fewer “trial and error” builds because the IDE catches mistakes sooner.

Readability and Syntax Differences

Groovy DSL is often praised for being very concise and flexible. You can omit parentheses, skip some punctuation, and write configuration that looks very close to plain English. The downside is that it can hide what is really a method call or property assignment.

Kotlin DSL is more explicit. You often use = to assign values, must write parentheses for functions like id("..."), and sometimes need to call helper methods like getByName("release"). This extra structure makes the script easier to read for people familiar with Kotlin, and safer for the IDE to analyze.

In short:

• Groovy DSL: Shorter, more “magical”, but sometimes harder to debug.
• Kotlin DSL: Slightly more verbose, but clearer and easier to maintain in the long run.

Migration: Can You Switch from Groovy to Kotlin DSL?

Yes, you can migrate an existing Android project from Groovy DSL to Kotlin DSL. Newer Android Gradle Plugin and official documentation even encourage using Kotlin DSL for new projects.

Typical migration steps are:

• Rename build.gradle files to build.gradle.kts (project and module level).
• Update syntax: string-based plugin IDs to id("..."), use = assignments, use type-safe accessors (for example, isMinifyEnabled).
• Fix any dynamic Groovy constructs that do not compile in Kotlin and replace them with Kotlin equivalents.

You can migrate gradually (module by module) and use both DSLs in the same multi-module project for a while, because each module’s build script is independent.

Android-Specific Considerations

In Android projects, the choice between Groovy DSL and Kotlin DSL does not affect whether your app code is written in Java or Kotlin. You can:

• Write the app in Java but use Kotlin DSL for Gradle.
• Write the app in Kotlin but keep Gradle in Groovy.

The DSL choice only affects how you configure Gradle, not the language of your app source code. However, many teams building Kotlin-based Android apps like having everything (app code + build scripts) in the same language for consistency.

Pros and Cons: Groovy DSL vs Kotlin DSL

Groovy DSL – Pros

• Mature and widely used in older Android and Gradle projects.
• Concise and flexible syntax, great for quick configuration and scripting.
• Lots of existing examples and StackOverflow answers written in Groovy.

Groovy DSL – Cons

• Dynamic typing means some errors only appear at build/run time.
• IDE auto-completion and refactoring are less powerful than with Kotlin.
• New Gradle and Android documentation increasingly use Kotlin DSL examples.

Kotlin DSL – Pros

• Statically typed, so you get strong type checking and better error messages.
• Excellent IDE support in Android Studio: auto-complete, navigation, refactoring.
• More readable and maintainable for Kotlin/Android teams in the long term.
• Preferred by Google for modern Android Gradle scripting.

Kotlin DSL – Cons

• Syntax can feel more strict and verbose when coming from Groovy.
• Initial migration from Groovy requires some effort and learning.
• Some older blog posts and answers may still show only Groovy DSL snippets.

How to Choose: Groovy DSL or Kotlin DSL?

There is no single “correct” answer, but here are some practical guidelines you can use for Android projects:

• Choose Kotlin DSL if you are starting a new Android app today, especially if your team is already using Kotlin for app code and you care about long-term maintenance and IDE support.
• Stay with Groovy DSL for now if you have a large, stable legacy codebase in Groovy, the team is comfortable with it, and you do not have the time or budget to migrate immediately.
• Plan a gradual migration to Kotlin DSL for multi-year projects, as the ecosystem and official docs are clearly moving in that direction.

Whichever you choose, remember that both DSLs configure the same Gradle engine. Your app’s runtime behavior does not depend on which DSL you use, only your developer experience does.

Conclusion

The difference between Groovy and Kotlin DSL in Android Gradle scripts is primarily about language, typing, and tooling—not about what your app can do. Groovy DSL is dynamic, flexible, and well established; Kotlin DSL is statically typed, IDE-friendly, and increasingly the modern standard for new Android projects.

If you want better auto-completion, safer refactoring, and a more consistent Kotlin-based codebase, Kotlin DSL is usually the better long-term choice. If your project is heavily invested in Groovy and you value quick, flexible scripting, Groovy DSL can still serve you well. The best option depends on your team’s skills, project size, and how long you expect the codebase to live.