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Skip 2024 Roadmap

Skip enables you to build the best possible apps, for the widest possible audience, using a single codebase. Our goal with Skip is to enable individuals and small teams to create apps for both the iPhone and Android using the native first-party toolkits for those platforms: SwiftUI and Jetpack Compose. We believe this is the best possible experience for users of iPhone and Android devices.

We spent 2023 building the underlying technology to enable this project. The SkipStone transpiler takes your code written in Swift for iOS and converts it into Kotlin for Android. The open-source SkipStack frameworks provide runtime support: they transparently bridge the various Darwin and iOS software layers into their Android equivalents. This includes SkipUI, which takes your SwiftUI interface and turns it into the equivalent Jetpack Compose code, as well as SkipFoundation, which bridges the low-level Foundation framework to the Java APIs used by Android apps. Bringing it all together is the Skip Xcode plugin that automatically runs the transpiler when you build your project and converts your entire Swift package into a buildable Android gradle project.

The end result is a magical development experience: you develop in Xcode and run your SwiftUI app in the iOS Simulator, and Skip seamlessly transpiles and launches your Compose app in the Android emulator. Change some code and re-run, and within seconds both your iOS app and Android app are rebuilt and run side-by-side, ready for testing. The Skip Tour video provides a taste of this process.

In 2024 we will be expanding our ecosystems of Skip frameworks beyond SwiftUI and Foundation. Aside from user interface widgets and operating system integration, a modern mobile app needs a variety of capabilities: graphics and animation, SQL databases, push notifications, media players, cloud storage, payment integrations, parsers for common data formats, cryptography, game technologies, et cetera.

There are many existing libraries, both 1st and 3rd party, for both Android and iOS that fulfill these needs. Our goal is not to re-invent them, but rather to build common abstractions atop them. For example, the new SkipAV framework for playing music and videos is not created from scratch, but is rather implemented on top of iOS’s AVKit and Android’s ExoPlayer. This enables Skip apps to take advantage of each platform’s best-in-class libraries that have matured over the years, while at the same time maintaining a single dual-platform API for developer convenience.

These frameworks are all free and open-source software that Android and iOS app developers can use in their apps. We sell the Skip transpiler itself, but the ecosystem of Skip frameworks can be used – independently of the Skip transpiler – whether or not you are a customer. We choose to make them free software not merely as a value-add for our own customers, but also to grant you, the developer, the confidence that anything you build with Skip will remain under your purview, and that you retain the agency to continue to iterate on your app, with or without the Skip transpiler.

The realization of genuinely native apps for both major mobile platforms, created from a single codebase in a single language, has been a dream for a long time. 2024 will be an exciting year.

Skip is Free for Free Software

Skip brings your iPhone app to Android. With Skip, you can create a modern SwiftUI app with the standard iOS development tools, and Skip transforms it into a Kotlin app for Android. With Skip you can iteratively design, build, test, run, debug, and deploy a single app for both major mobile platforms using a single language (Swift) and a single IDE (Xcode). Watch our 12-minute tour for a glimpse of the magic.

Today we are pleased to announce that Skip will be free for all free open-source software.

There are two halves to the Skip project. The first is SkipStone, our integrated Xcode plugin that transpiles your Swift source code into Kotlin as part of the normal build process. SkipStone is commercial software. It is currently a public technology preview, with early adopter pricing to be announced soon1.

The other half is Skip’s ecosystem of libraries and frameworks, which is free and open-source software. These frameworks constitute the essential building blocks of any modern application, and include low-level adaptors from Darwin’s Foundation API to the equivalent Android Java API (skip-foundation), as well as the high-level SwiftUI user interface widgets that are manifested by Jetpack Compose views on Android (skip-ui). In addition, the growing constellation of community frameworks at github.com/skiptools provides essential functionality such as SQL database support, media player components, and more.

These frameworks are free and open-source software whose advancement will rely heavily on community contributions. And so we’ve made the SkipStone transpiler free, for free software. What this means is that Skip can be used – without cost – for building projects that consist exclusively of source code licensed under one of the General Public Licenses as published by the Free Software Foundation.

This applies not just to framework development, but also to your own app projects: if your iOS app is free software, then Skip can be used to transpile it into an equivalent free Android app. In this way we hope to encourage and support the proliferation of genuinely native dual-platform apps created with the Skip transpiler and powered by the community-supported ecosystem of high-quality libraries and frameworks.

Skip is advancing by leaps and bounds, but it is still a technology preview. You can use it today to create a greenfield app for iOS and Android, provided you are willing to iterate carefully and to work around (or implement and contribute!) some missing pieces. Read the getting started guide to begin the adventure.

The reward will be well worth the effort. Your genuinely native app, created from a single modern Swift codebase, running on both Android and iOS, will be priceless.

More details can be found at our FAQ and documentation. Follow us on Mastodon at mas.to/@skiptools or with RSS.

  1. Commercial pricing will be announced soon, but you can qualify for an early adopter discount by registering during the tech preview period.

Announcing the Skip Technology Preview!

We’re thrilled to announce the tech preview of Skip: dual-platform app development in Swift.

Screenshot

You write a modern iPhone app, and Skip transpiles it into a native Android app in real time.

Skip is the only solution that enables the creation of genuinely native apps for both iOS and Android with one language, one team, and one codebase.

Check out the video tour and visit the FAQ and documentation to get started. Sign up at skip.dev to be notified about future updates.

Happy Skipping!