Amper

Amper is a tool for project configuration. Its goal is to improve the project configuration experience and toolability, that is, the support inside the IDE, while also providing a smooth out-of-the box experience. We believe that this can be achieved by:

providing a developer- and IDE-friendly declarative configuration DSL - to simplify not only the initial setup but also improve maintainability and let an IDE assist with automatic configuration reliably;
bundling a curated set of compatible toolchains and extensions - to support the majority of the scenarios without the need to find compatible plugins;
carefully choosing the extensibility points - to keep the overall mental model and UX of the configuration consistent and to avoid unexpected third-party code execution.

In essence, we aim to achieve a similar well-thought-out and well-tested experience as with JetBrains IDEs.

We’re currently looking at various aspects, including the configuration of projects for the purpose of building, packaging, publishing, and more. At its current stage, however, the focus is primarily on configuring projects for the purpose of building.

While the current use case is Kotlin and Kotlin Multiplatform, Amper also supports Java and Swift (as a requirement for multiplatform). However, the same approach to configuration could work for other languages and technology stacks in the future.

Amper is implemented as a Gradle plugin and uses YAML for its project configuration format. The goal right now is to validate the user experience, which is why we have chosen to build on a well-tested build tool like Gradle, providing a configuration layer on top of it.

Supported features:

Creating and running JVM, Android, iOS, Linux and macOS applications.
Creating Kotlin Multiplatform libraries.
Running tests.
Mixing Kotlin, Java and Swift code.
Using Compose Multiplatform.
Multi-module projects.
Gradle interop, including combining Amper and Gradle modules in one projects.
Gradle-compatible project layout for the smooth migration of existing Gradle projects.
Code assistance for module manifest files in IntelliJ IDEA and Fleet.

Planned features:

More product type and platforms, such as watchOS, Windows, etc.
Platform-specific test types, including android instrumented tests.
Native dependencies support, such as CocoaPods, Swift Package Manager.
Integration with Gradle version catalogs.
Packaging and publication.
Build variants support.
Extensibility.
Workspaces (organizing multiple modules together).
Support more Kotlin and Kotlin Multiplatform scenarios and configurations out-of-the-box.

Check the FAQ for more question and the list of known issues.

Join the Slack channel for discussions, submit your ideas in the tracker and share your feedback here.

For a quick start:

How to Try

There are multiple ways to try Amper:

In IntelliJ IDEA 2023.3, for JVM and Android projects.
In JetBrains Fleet, for the JVM, Android, and Kotlin Multiplatform projects.
Using Gradle to build Amper projects from the CLI or CI/CD.

Examples

Basics

Here is a very basics JVM "Hello, World!" project:

The main.kt and MyTest.kt files are just regular Kotlin files with nothing special in them. The interesting part is module.yaml, which is the Amper manifest file. For the above project structure, it would simply be:

# Produce a JVM application 
product: jvm/app

That's it. The Kotlin and Java toolchains, test framework, and other necessary functionality is configured and available straight out of the box. You can build it, run it, write and run tests, and more. For more detailed information, check out the full example.

Multiplatform

Now, let's look at a Compose Multiplatform project with Android, iOS, and desktop JVM apps, with the following project structure in Fleet:

Notice how the src/ folder contains Kotlin and Swift code together. It could, of course, also be Kotlin and Java. Another aspect to highlight is the shared module with the common code in the src folder and the platform-specific code folders src@ios and src@android (learn more about project layout).

Here is how ios-app/module.yaml manifest file looks:

# Produce an iOS application
product: ios/app

# Depend on the shared library module: 
dependencies:
  - ../shared

settings:
  # Enable Compose Multiplatform framework
  compose: enabled

This is pretty straightforward: It defines an iOS application with a dependency on a shared module and enables the Compose Multiplatform framework. A more interesting example would be shared/module.yaml:

# Produce a shared library for the JVM, Android, and iOS platforms:
product:
  type: lib
  platforms: [jvm, android, iosArm64, iosSimulatorArm64, iosX64]

# Shared Compose dependencies:
dependencies:
  - $compose.foundation: exported
  - $compose.material3: exported

# Android-only dependencies  
dependencies@android:
  # integration compose with activities
  - androidx.activity:activity-compose:1.7.2: exported
  - androidx.appcompat:appcompat:1.6.1: exported

# iOS-only dependencies with a dependency on a CocoaPod
#   note that CocoaPods dependencies are not yet implemented in the prototype     
dependencies@ios:
  - pod: 'Alamofire'
    version: '~> 2.0.1'

settings:
  # Enable Kotlin serialization
  kotlin:
    serialization: json
  
  # Enable Compose Multiplatform framework
  compose: enabled

A couple of things are worth mentioning. First, note the platform-specific dependencies: sections with the @<platform> qualifier. The platform qualifier can be used both in the manifest and also in the file layout. The qualifier organizes the code, dependencies, and settings for a certain platform. Second, the dependencies: section allows not only Kotlin and Maven dependencies, but also platform-specific package managers, such as CocoaPods, Swift Package Manager, and others.

Naturally, these examples show only a limited set of Amper features. Look at the documentation, tutorial, and example projects to get more insight into Amper’s design and functionality.

More examples

Check our more real world examples:

JVM "Hello, World!"
Compose for iOS, Android and desktop.
Multiplatform project with shared code.
Gradle interop
And others

y9san9 / amper