Kotlin Multiplatform Newsletter #9
Kotlin 2.3.20 released, Room supporting KMP for JavaScript and WASM, context-aware recomposition budgets for Compose, IntelliJ code selection plugin, how Compose and SwiftUI work under the hood, KMP jobs at Touchlab, and more.
The Log
The only Kotlin Multiplatform and Compose Multiplatform news you actually need to know.
Here are the main highlights:
- Gradle: Compatibility with Gradle 9.3.0 and Kotlin/JVM compilation uses the Build tools API by default.
- Maven: Simplified setup for Kotlin projects.
- Kotlin compiler plugins: Lombok is Alpha and improved JPA support in the
kotlin.plugin.jpa plugin.- Language: Support for name-based destructuring declarations.
- Standard library: New API for creating immutable copies of
Map.Entry.- Kotlin/Native: New interoperability mode for C and Objective-C libraries.
Room 3.0 is a major breaking version of the library that focuses on Kotlin Multiplatform (KMP) and adds support for JavaScript and WebAssembly (WASM) on top of the existing Android, iOS and JVM desktop support.
Expect Actual
Technical deep dives, or solving the "how-the-hell-do-I-test-this" problems.
Practical Kotlin Deep Dive (Jaewoong Eum) takes you beneath the surface of Kotlin, exploring not just what the language does, but how it works and why it was built that way.
From foundational concepts through coroutines, compiler architecture, and Kotlin Multiplatform, this book connects everyday coding patterns to their underlying mechanisms.
Integrating Apple Pay and Google Pay in a Kotlin Multiplatform app sounds straightforward until you actually try it. Different SDKs, different lifecycles, different UI entry points. Suddenly, your shared UI is full of platform checks, and the platform source sets are packed with empty stubs just to make things compile.
A cache strategy built around how data actually changes - not how often users open screens. The naive approach to fetching data is simple: the user opens a screen, you fetch the latest data. Every single time. It works. But it’s also incredibly wasteful in ways that compound quickly once you think about the actual nature of the data you’re fetching.
To understand discussions about Gradle, it's necessary to understand how things are named—and that can be quite confusing. This is a short article to summarize the various concepts and list tips and tricks I've learned over the years.
Kotlin is getting a new concept that will widen the possibility of extension functions. The feature is still experimental in the latest Kotlin version, which makes it the perfect time to try them out.
LazyColumn
Compose Multiplatform tips, tricks, and code snippets.
The Compose ecosystem has solid tooling for tracking recompositions. Layout Inspector shows counts and skip rates. Compiler reports surface stability issues. Rebugger logs argument changes. ComposeInvestigator traces recomposition causes automatically. Each of these tools answers an important question well.
But none of them answer this one:
"Is this composable recomposing too much for what it does?"
In this article, you'll explore the full pipeline that transforms a
@Preview annotation into a rendered image, tracing the journey from the annotation definition itself, through ComposeViewAdapter (the FrameLayout that orchestrates the render), ComposableInvoker (which calls your composable via reflection while respecting the Compose compiler's ABI), Inspectable (which enables inspection mode and records composition data), and the ViewInfo tree that maps rendered pixels back to source code lines.The user sees a smooth screen transition, a list that populates, a dialog that appears at just the right moment. What they don’t see is the coroutine that launched in the background, the listener that was cleaned up on exit, the scope that held everything together just long enough to be useful. All that happens off-screen. In the pit lane.
The Dependency Graph
Curated libraries, tools and plugins that won't break your Gradle build.
- Rebound
Compose recomposition budget monitor — catch runaway recompositions before they ship. Kotlin compiler plugin + IDE cockpit + CLI. Full KMP support. - Composable Selection
A lightweight IntelliJ plugin that selects the nearest function call at your cursor. Press again to expand to the parent call — effortless navigation through nested Kotlin function hierarchies. - KPayment
A Kotlin Multiplatform payment library with Compose Multiplatform UI components for Google Pay and Apple Pay across Android, iOS, and Web. One API, shared types, reactive availability detection, and platform-native payment buttons.
Target: Production
Showcase of real-world apps proving KMP is ready for prime time.
Ship your next iOS & Android app in days with Kotlin Multiplatform
Skip the boring setup. KMPShip is a KMP boilerplate with Firebase auth, RevenueCat, push notifications, CI/CD, and more already wired up. Go from idea to App Store & Google Play in days, not weeks.
kevinguitar
Careers
Kotlin Multiplatform job postings and opportunities.
wellfound • Where startups and job seekers connect.
🤝 Connect directly with founders at top startups - no third party recruiters allowed.
💸 Everything you need to know, all upfront. View salary, stock options, and more before applying.
✌️ Say goodbye to cover letters - your profile is all you need. One click to apply and you're done.
✨ Unique jobs at startups and tech companies you can’t find anywhere else.
This role will involve directly building client applications using the latest Swift-based tools and Xcode, and coding and interacting with Kotlin libraries. It will include helping to define how our tools will evolve to serve iOS developers better, and directly working on the tools and libraries we publish.
This is a contract relationship for project-based engagements. Touchlab has been at the forefront of Kotlin Multiplatform (KMP) since the first Kotlin code ran on an iPhone. We’ve made significant contributions to the KMP ecosystem and are excited to continue growing and improving the community. We’re looking for talented developers with a strong foundation in one or more areas of software development in the competencies listed below. This is a unique opportunity to work on challenging and innovative projects across different industries, from startups to established enterprises.
Superb gathers all the tools to open, run and grow your hospitality business — in one platform. We are looking for one more remote Kotlin Multiplatform Product Engineer to join our team and play a key role in shaping our mobile products for restaurateurs. In this role, you will work on delivering seamless experiences across multiple platforms using KMP, ensuring high performance and maintainability.
🚀 Get Featured!
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🤝 Support the Build
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✍ Code Review
This newsletter is curated and written by a real human being. I’m always looking for ways to optimize the build. Was there something you liked or disliked in particular? Or did you find a bug in this issue? Simply reply to this email - I read every comment from the community and take your feedback into account for the next release.
Until next time,
Stay platform-independent!
Bogdan • Founder of commonMain.dev