Kotlin support is now available in BlueJ 6.0! 💙 Developed in collaboration with the Programming Education Tools group at King’s College London, Kotlin support brings a modern JVM language into one of the most established environments for teaching introductory object-oriented programming. With Kotlin in BlueJ, students can keep the familiar objects-first workflow – visual class diagrams, the object bench, and direct object interaction – while writing clearer, more concise code. Download BlueJ 6.0 and get started with Kotlin in BlueJ

🤖 Want to try building a Kotlin application with Claude Agent? Follow this hands-on tutorial to create a task manager app with Kotlin and Spring Boot directly in IntelliJ IDEA. You’ll learn how to use Claude Agent to plan the application, implement the features, review the generated changes, run tests, and refine the UI step by step. Start building👇

📣 There's still time to apply for the Kotlin Foundation Grants for Library Authors. Applications close on July 14, 2026.

🛠️ Switch your Kotlin Multiplatform project from CocoaPods to SwiftPM dependencies with Junie. Working with a KMP module that relies on CocoaPods dependencies and planning to try the experimental SwiftPM import integration? This step-by-step guide shows how to use Junie and a Kotlin AI skill to assist the migration process. You’ll learn how to: ➡️ Set up Junie CLI and install the migration skill ➡️ Start the migration in your project ➡️ Review the generated changes in Git ➡️ Test the migrated project Read the guide👇

set the channel topic: Welcome to K Slack. The topic is Kotlin. Be Kind. Be Considerate. CoC and guidelines https://kotlinlang.org/docs/slack-code-of-conduct.html#slack-code-of-conduct.md

K*Introducing the Kotlin Benchmark* An open, reproducible benchmark for evaluating AI coding agents on Kotlin software engineering tasks. It uses 105 issues from active open-source Kotlin repositories, validated by each project’s own test suite. Beyond resolution scores, the leaderboard reports average token consumption and latency, so you can weigh each setup on cost and speed, not just correctness. This is our first iteration. Newer models are already being evaluated, with updated results coming soon. See the leaderboard and learn more ⬇️

📣 Library grant program – last call! There's still time to apply for a Kotlin Foundation grant for Multiplatform library authors. Applications are open 📆 until July 14, 23:59 CEST. Learn more and apply here 👇

📢 Kotlin 2.4.10 is here! This release brings performance improvements and bug fixes. Changelog: ➡️ kotl.in/x74s6p

Join the Kotlin birthday party by creating your own postcard! Leave a birthday wish or bold prediction for Kotlin's future. You can also upload your photo and celebrate alongside Kodee. Once you've created your postcard, drop it in this thread. Let's fill the channel with birthday wishes for Kotlin's future! 💜 kotl.in/wj8xba

kodee electrified Kodee is more than Kotlin’s mascot. What began as an idea for bringing more warmth and personality to the programming language evolved into a vibrant character shaped by research, creative iteration, and feedback from the Kotlin community. With an expressive design, tech-savvy charm, and playful spirit, Kodee has become a symbol of Kotlin’s inclusive and developer-friendly culture. Discover the story behind Kodee’s journey from concept to community icon👇

K*Help us understand where AI falls short with Kotlin – and get rewarded!* At Kotlin, we’re working to build an ecosystem that better supports AI-powered workflows. We are looking to collect detailed examples of where and how AI tools struggle with Kotlin, and we would love your help. See here for how to get involved. We look forward to your responses and to building a stronger Kotlin ecosystem together 💪

🚀 Already know Kotlin? Reuse your skills to build for Android, iOS, desktop, and web. RevenueCat Shipaton 2026 is your chance to turn your next app idea into a real product with Kotlin Multiplatform and Compose Multiplatform. Build and launch your app between August 1 and September 30 and compete for the Ship Kotlin Everywhere Award. Share your journey with others to earn extra points. Learn more and register 👇 kotl.in/ei3top

Please share your feedback 👇

👋 Using Compose Multiplatform and want more people to know about your app? We’re refreshing the Compose Multiplatform app showcase, and we’re after the beautiful stuff: apps where the UI makes people ask what it’s built with. It’s a good fit if your app: • is live in production or public beta; • uses Compose Multiplatform for at least part of the UI; • is available on the App Store or Google Play; • looks good enough that you’d screenshot it yourself 🤘🏻. Selected apps may be featured on Kotlin and JetBrains websites, social media, in talks and other materials, with a link so people can try them. You don’t have to be a household name yet: established products and fast-growing apps are both interesting to us, from company products to indie projects and open source. Submit here: surveys.jetbrains.com/s3/Compose-Mult…

Hey everyone! A month ago we shared that Shipaton 2026 is on, and since then the KMP category has been filling up with builds. If you missed it or filed it under “later”, here’s your reminder: there are still six weeks left, and that’s genuinely enough. Proof: last year Rehaan entered with zero KMP experience, learned it during the build window, shipped his app Posturely to the stores in time, and took 2nd place in our category. In his words:

“Shipaton showed me how quickly you can learn and build with Kotlin Multiplatform, especially when using AI as a learning partner. Finishing my first KMP project in time, and then placing second, was an incredible surprise.”

The short version of what’s at stake: build and ship a mobile app with KMP by Sep 30, compete for the Ship Kotlin Everywhere Award, $30,000 across three winners, top app goes on a Times Square billboard. Starter Guide, AI Guide, IntelliJ IDEA Ultimate and Junie access included. And this Tuesday (Aug 25, 9am PT / 6pm CEST) we’re going live with RevenueCat: a KMP talk by @zsmb, category-winning tips from @Pamela Hill Hill-Galloway (she judged it last year), and open Q&A. Great place to start if you’re on the fence 👉 All the details and registration: kotlinlang.org/lp/shipaton

📢 Kotlin 2.4.20 is out! Here are some of the highlights: ✅ Standard library: Support for coroutine stack trace recovery, new functions for checking the equality and uniqueness of collection elements, and new overloads for kotlin.test assertion functions ✅ Kotlin/Native: New Swift export features, improved incremental compilation, and automatically generated Package.swift files for SwiftPM dependencies ✅ Kotlin/Wasm: Changes to top-level

require()

calls in

@JsFun

declarations, improved initialization order of companion objects, support for Wasmtime in the Kotlin Gradle plugin, new compilation modes, and reduced binary size for functional interfaces ✅ Kotlin/JS: A new DSL for browser testing, support for exporting suspending lambdas as async functions, improved exportability of data classes ✅ Gradle: Support for Gradle 9.7.0 and improved reporting in the Problems API ✅ Build tools API: Support for new targets: Kotlin/JS, Kotlin/Wasm, and Kotlin metadata ✅ Kotlin compiler: kotlinr runner command and a separate native image

Kotlin Toolchain 0.12 is out! kodee happy What's new: • Multiplatform library publishing across all Kotlin platforms (previously JVM-only) • Preview of Wasm app support: Run with

kotlin run

• Compose Hot Reload from the CLI • An MCP server for agents 📝 Release notes: kotl.in/0.12.0-slack youtrack It’s still in Alpha, so we'd love your feedback here or on YouTrack

📣 Kotlin’s annual developer survey is out! We’d love to hear from you. Help us improve the language, tools, and overall developer experience by sharing your thoughts. 👉 Take the survey

IS KOTLIN'S GOLDEN AGE OVER?

It’s a bold question to ask @jw, someone who was there when Kotlin became an official Android language. His answer is not quite what you might expect. His takes on AI, Swift vs. Kotlin, Flutter, Gradle, open source, and the Kotlin feature that annoys him might also surprise you. Watch Jake Wharton in conversation with @Vitaly Bragilevsky👇

K Watch the _**_ video by Márton Braun 👇

🎉 KotlinConf 2027 kicks off in Kraków! 🎉 Hey everyone! We're excited to bring the Kotlin community together in Poland on April 21–23, 2027. Super Early Bird tickets are available – grab yours and join us. kodee walking kotl.in/conf27-seb-slck

📍 The Kotlin roadmap has been recently updated! Our key focus areas: ✨ Language evolution – keeping Kotlin concise and expressive, and prioritizing ergonomics and safety over ceremony. 📱 Kotlin Multiplatform – becoming the foundation for modern cross-platform apps through a solid iOS experience, mature web targets, and reliable IDE tooling. 🧩 Staying agnostic – supporting developers no matter their tools or targets. 📦 The experience of third-party ecosystem authors – simplifying the development and publication process for Kotlin libraries, tools, and frameworks. Explore concrete plans across Language, Compiler, Multiplatform, Tooling, and Ecosystem areas, including Ktor and Exposed, plus roadmap items we’ve completed since February. Explore what's next 👇 kotl.in/3ylsia

Hi All, I still remember the day I decided to turn the Slack I had for Ktor into something broader, i.e. Kotlin. We started with a handful of us, the five or so from the IRC channel, plus around ten people who were here for Ktor. The community grew, and became what it is today. Nearly 75K of you, learning, helping each other, and being part of the wonderful community that is Kotlin. Yesterday I announced that I've moved on from JetBrains. I didn't want to miss the chance to say thank you to all of you for believing in Kotlin and helping build this amazing community. Take care of yourselves, and of this community. Kindness, understanding, and empathy are sorely missing in this world. Let's do our part to make sure they stay here. Thank you for everything!

The KotlinConf 2027 Call for Papers is now open! 🎤 Have a Kotlin story, lesson, or idea worth sharing? Submit your proposal for your chance to take to the stage in Kraków and share your experience with the Kotlin community. Apply here: kotl.in/gnmin6 Planning to join us as an attendee? There are only 9 days left until KotlinConf 2027 ticket prices go up! Get yours now and join us in Kraków, Poland, April 21–23: kotl.in/vl4a8n

📢 Kotlin 2.4.21 is here! This release brings performance improvements and bug fixes. Changelog: ➡️ kotl.in/8mktk1

kodee happy The Kotlin Multiplatform Contest is live! kodee happy Students and recent graduates: Turn your idea into a cross-platform project with Kotlin Multiplatform and compete for one of three trips to KotlinConf 2027 in Kraków! Submit by December 7 kotlinconf.com/contest Don’t forget to join the #C04FWDRM6TA channel for updates and help along the way. We can’t wait to see what you build!

Hey everyone! 👋 We’d love your help shaping future KotlinConf events. Software development is changing so quickly. For us, meeting in person to share first-hand experience and fresh perspectives feels more valuable than ever. What makes a conference worth your time in the AI era? Deep dives? First-hand production case studies? Chats with the actual humans behind the tools? Meeting people you’ve only chatted with online? Or the party? Still AI-proof, we hope 🙂 We’ve put together a five-minute survey and would really appreciate your thoughts, whether you’ve been to KotlinConf before or are just curious. Tell us what you’d like more of, what’s missing, and what would make the trip worthwhile for you: surveys.jetbrains.com/s3/KotlinConf-Survey2026 After completing it, you can also enter a draw to win one of three KotlinConf 2027 tickets. Thanks for sharing your thoughts with us! 💜

📢 The Kotlin compiler is moving to JDK 17 as its minimum runtime. Here's the plan: • 2.5.0-Beta1: A warning when you run the compiler on a JDK older than 17. • 2.5.0-Beta2 and 2.5.0: An error, with a flag to keep using your current JDK for now. • 2.5.20-Beta1 and later: JDK 17 or newer is required. If your machines or CI still run the compiler on an older JDK, now is a good time to plan the update. 👉 If you have a use case we might be missing, tell us in KT-88173

Hey everyone 👋 We’re 24 weeks away from KotlinConf 2027 (April 21–23, Kraków). Sounds far, but right now is when most doors into the conference are open. Here’s a quick map of ways to be there, feel in person how strong this community is, and see Kraków in spring while you’re at it. 🎤 Speak. The Call for Papers is in full swing until November 27. We’re waiting for your talks on everything Kotlin: mobile and multiplatform, backend, web, developer tooling, libraries, language best practices, and of course AI-powered products and agentic engineering. The strongest talks are stories: what you tried, what you decided, and what you’d do differently. Experiments and “it didn’t quite work” lessons absolutely count, and we read every proposal. Submit: kotlinconf.com/speakers 🙌 Volunteer. If you’ve ever wondered how a conference like this is made, this is your backstage pass. You give up to 10 hours across three days, work shoulder to shoulder with the KotlinConf crew (it bonds people surprisingly fast), and when you’re off shift you attend talks for free, with lunch, the party, and a volunteer uniform on top. Apply by December 21: kotlinconf.com/volunteers 🎟️ Attend. Tickets are on sale. Prices increase gradually through the sales period, so the current price is the best one still available: kotlinconf.com 👥 Bring your team. Honestly the most fun way to do KotlinConf. Teams booking together get group tickets with an extra discount, up to 7% for bigger groups. kotlinconf.com/registration 🏢 Show what you build. Want to show the community your product, or how your team works with Kotlin? The expo floor puts you in front of 2,000+ developers. There are classic booths, and we’re open to creative formats too: a coding challenge, a community lounge, or your own idea. kotlinconf.com/partners (or just ping @Kathrin Petrova) See you in Kraków kodee walking