Getting started with JetBrains development after Fleet discontinuation

JetBrains stopped all Fleet updates and distribution on December 22, 2025. The company decided that maintaining two overlapping product lines, Fleet and the IntelliJ-based IDEs, created confusion and diluted focus. Rebuilding the full capabilities of IntelliJ-based IDEs inside Fleet did not provide enough value. Fleet users must now transition to new workflows or existing IntelliJ-based tools. The company stopped all Fleet updates and distribution in late 2025. This decision stemmed from the difficulty in differentiating Fleet from the established IntelliJ product line. Many components from the Fleet project now power modern JetBrains IDEs. The focus has shifted entirely to agentic development environments like Air.

The evolution into Air

Fleet has evolved into Air, which is an agentic development environment. Air combines the speed and lightweight feel of the Fleet platform with a new agentic experience for developers. The Fleet team chose to stop competing with traditional code editors and instead build a product focused on agentic workflows. This new direction follows the observation that the best path forward involves strengthening AI workflows within existing IDEs. Developers now delegate meaningful tasks to agents, such as updating tests, cleaning code, refactoring modules, or exploring unfamiliar code paths. These tasks run asynchronously and return full patches. The developer guides the agent and reviews the output. This agentic loop relies on structured task definition, context assembly, multiple asynchronous runs, isolated execution, and review-first workflows. This process differs from the classic IDE workflow because it does not rely on immediate, synchronous control. Will the agentic model of Air eventually replace the synchronous debugging workflows found in IntelliJ?

Kotlin Multiplatform in the IntelliJ ecosystem

JetBrains abandoned the plan for a standalone Kotlin Multiplatform IDE. The company deprecated support for KMP on Fleet to focus efforts on improving KMP support on the IntelliJ Platform. This shift responds to feedback from users who wanted KMP features available in both IntelliJ IDEA and Android Studio. Google’s official support for KMP on Android, which began in May 2024, also strengthened this demand. KMP allows code sharing across platforms by compiling Kotlin code into different formats. Kotlin/Native produces code for platforms like iOS and macOS. Kotlin/JVM creates bytecode for Android and server-side applications. Kotlin/JS enables the creation of web applications in Kotlin. Developers can use the IntelliJ code-processing engine for Swift and all Kotlin support. This ensures that the transition from Fleet to the IntelliJ ecosystem maintains high functionality for multiplatform developers.

Android Studio for mobile developers

Android Studio remains the official IDE for Android app development. It provides Android SDK integration, AVD management, and specialized profilers for CPU, memory, and energy. Developers who require intensive mobile-specific features such as the Visual Layout Editor, AVD manager, or specialized profilers should use Android Studio rather than attempting to use IntelliJ IDEA for their primary mobile development workflows. Android Studio needs a very high amount of RAM and a high-end processor to run smoothly, which can be unaffordable for everyone. Because Google maintains the product, the IDE receives frequent updates to keep it bug-free. It provides complete, first-class Android tooling including APK analyzer and Firebase integration. Users can also manage Android emulator and device tools directly within the IDE.

Full-stack development with IntelliJ IDEA

IntelliJ IDEA supports developers working across backend and frontend services. The Ultimate edition provides advanced web, enterprise, and database tools. For those working on Kotlin Multiplatform projects, IntelliJ allows users to open, navigate, and build projects. It provides the necessary tools for JVM-based development. Many teams use IntelliJ IDEA for backend work and Android Studio for app development. You already know the basics of Gradle, so concentrate on the version catalog structure when setting up your projects. Space is available to users of both Fleet and IntelliJ IDEA to facilitate remote development. Space provides Git hosting, CI/CD, package repositories, chats, documents, and project management. This solution moves the heavy load to a remote server, which helps developers who are limited by the power of their local computers.

KMP cross-language functionality

KMP development in the current ecosystem allows for cross-language navigation. When a developer uses the Show Usages action on a Kotlin function, any invocations from Swift code appear in the results. If a single match exists, the IDE displays the associated file. Refactoring is also cross-language. Renaming a MainViewController type applies the change across both Kotlin and Swift modules. Debugging allows a developer to set a breakpoint in Swift code, view values and the call stack, and then step into a Kotlin call. This functionality ensures that developers do not need to switch to a different editor when working with native code in a multiplatform project.

Migration and dependency management

Migrating projects to Android Studio requires adapting to a new project structure and build system. If a project already uses Gradle, a developer can import it directly. To do this, the developer clicks File, then New, then Import Project and selects the directory. For non-Gradle projects, a developer can create a new empty project and move source files into the correct locations. A developer must enter a name for the app project, specify the location, select form factors, and click Add No Activity. After moving the code, unit tests, and resources, the developer clicks File, then Project Structure to modify properties in the Properties tab.

Gradle version catalogs provide a way to manage dependencies and plugins in a scalable way. A developer creates a libs.versions.toml file in the root project’s gradle folder. The developer defines variables in the versions block and dependencies in the libraries block. It is best to use kebab case for names, such as androidx-ktx, to help with code completion.

The Fleet Public Preview Program requires a login and periodic connection to JetBrains servers to verify the project. This verification checks if the project is local, public on GitHub, or private with fewer than three committers. The connection does not send source code or file names to JetBrains. For those with a paid Fleet license, the system only performs license verification with a JetBrains Account. Use Android Studio for dedicated Android app development and use IntelliJ IDEA for full-stack or enterprise development.