Talking Kotlin

Sebastian and Márton host a special, audio-only episode where they discuss everything that’s new and noteworthy in the Kotlin 2.3 release. They touch on new language features like the unused return value checker and explicit backing fields, previously added features that became stable in this release, new APIs for time and UUID handling in the standard library, and improvements across all Kotlin platforms — from Native to Wasm and JS. Resources: What’s new in Kotlin 2.3KotlinConfGolden Kodee Community AwardsHosts: WebsiteBlueskyWebsiteBlueskyTimeline: (0:00) Intro (1:13) Nested type aliases (stable) (1:46) Data-flow based exhaustiveness checks (stable) (3:28) Return statements in expression bodies (4:19) Unused return value checker (experimental) (12:57) Explicit backing fields (experimental) (18:51) Context-sensitive resolution (experimental) (20:11) Clock and Instant in the standard library (stable) (21:52) UUID v7 support and better parsing (26:14) Java 25 bytecode (26:36) Faster Native release builds (27:45) Swift Export: enums and varargs (29:08) C and Objective-C library import (beta) (30:49) Apple target support changes (32:15) Fully qualified names in Kotlin/Wasm (34:10) New exception handling for wasmWasi (35:32) Suspend function export to JS (37:51) LongArray export to JS (38:40) Unified companion object access in JS (41:05) @JsStatic inside interfaces (41:43) Default exports in JS (43:45) Compose stacktraces for minified Android apps (45:23) Breaking changes 🐜 (46:14) Documentation updates (47:24) KotlinConf, Golden Kodees Awards (48:11) Wrap-up

Sebastian and Márton talk to Vadim Briliantov, the Technical Lead for Koog: an agentic framework built by JetBrains. We learn about what AI agents are, and why building them in Kotlin with Koog is a great choice. We also discuss all the different ways AI agents can connect to other systems and your existing code, and look at advanced features for agents like custom strategies, model switching, and history compression. Resources: JetBrains/koog on GitHubKoog DocumentationHosts: WebsiteBlueskyWebsiteBlueskyGuest: LinkedInMediumGitHubBlueskyTwitter/XTimeline: (0:00) Intro (1:11) Vadim’s history at JetBrains (4:21) What’s an AI Agent? (5:47) Koog! (7:12) Applications for agents (12:43) Koog’s building blocks (15:05) Strategies, feedback loops (23:55) The Kotlin DSL (26:12) Persistent state (29:48) Subgraphs (32:33) Tools (39:52) MCP support (and A2A) (44:01) Entry point and type safety (49:39) Spring and Ktor support (51:27) LLM Providers (53:30) Model switching (56:02) History and memory (59:22) Enterprise-ready (1:02:12) History compression (1:11:47) Markdown?! (1:14:37) What’s next? (1:18:22) Going open-source (1:20:32) Conclusion

Sebastian and Márton chat with Marcin Moskała about coroutines. Resources: Coroutines Mastery courseCoroutines | Kotlin Documentationkotlinx.coroutinesTaming Asynchronous Beasts | Marcin MoskałaCoroutine Debugging in IntelliJ IDEA | Alexey MerkulovLifecycles, Coroutines and Scopes | Alejandro Serrano MenaCollect Like a Pro | Manuel VivoUntangling Coroutine Testing | Márton BraunJetBrains/lincheck – Concurrent testing framework#talking-kotlin on Kotlin SlackHosts: WebsiteBlueskyWebsiteBlueskyGuest: kt.academyTimeline: (0:00) Introduction (1:18) Branding discussion (3:23) Handling preconceptions (4:54) What are coroutines? (7:17) Lightweight threads? (11:07) Where coroutines live (13:27) Sequence Builder Example (17:37) The design of coroutines (20:52) What Makes Coroutines special vs other languages? (26:56) Coroutines vs Loom (34:55) Easy to start, hard to master (41:07) Common mistakes (49:33) Flows (58:52) Thinking about Flows (1:02:41) Derailing the conversation (1:03:55) Flows for single values (1:12:27) Structured concurrency (1:18:53) The 4 advantages (1:24:40) Seb tries web dev / The web is broken?! (1:31:15) collectAsStateWithLifecycle (1:32:00) Gardening break (1:36:23) Scopes and contexts (1:43:22) Testing coroutines (1:50:29) Lincheck (1:51:32) Turbine (1:55:05) Coroutines Mastery course (2:01:43) Wrap-up

Sebastian and Alex chat about the kotlinx.rpc project, in a special episode recorded in the Munich JetBrains office. They explore all the different components of the library, how you can use it to define RPC services and clients, integrate with Ktor and existing gRPC definitions, and more. While the library is still experimental, it’s already feature-packed, and it has ambitious plans for the future! kotlinx-rpc on GitHub#kotlinx-rpc on Slackkotlinx.serialization on GitHubgRPC Host: Sebastian Aigner WebsiteBluesky Guest: Alex Sysoev LinkedInGitHub

Sebastian and Márton are joined by Denis Borisevich from RIEDEL Communications, and learn about how Kotlin is used behind-the-scenes to power media, sports, and entertainment broadcasts watched by millions around the globe. Tune in for an exciting story about how Kotlin, Ktor, and Arrow are being used in production for a use case where robust software is mission-critical. Resources: Riedel CommunicationsTornadoFXUnsigned integer typesArrowKtorEurovisionHosts: WebsiteBlueskyWebsiteBlueskyGuest: LinkedInTimeline: (0:00) Introductions (2:42) Events powered by Riedel (3:50) The Kotlin part (6:44) Routing video signals (9:12) Error handling in milliseconds (10:31) The Kotlin part, continued (13:29) TornadoFX! (19:19) On introducing Compose (23:30) Java to Kotlin migration (26:30) Learning Kotlin after C++ (28:44) Unsigned ints in Kotlin (32:09) Arrow! (33:00) Server-side Kotlin (36:25) Functional programming (42:10) Why Kotlin over others? (45:55) Kotlin/Java interop (47:12) A 2-week long test suite (51:35) Confidence in Kotlin (53:05) Future plans (56:00) Wrap-up

Sebastian and Márton chat with Rod Johnson, the creator of the Spring Framework. Rod tells the story of how Spring was born more than two decades ago, and shares his recent journey of coming back to the JVM and discovering all the fun of being a newcomer to Kotlin. Resources: Expert One-on-One J2EE Design and Development: Rod JohnsonOh the Places You'll Go!Shoulders of Giants: Languages Kotlin Learned From | Andrey BreslavRevamping and Extending Kotlin's Type System | Ross TateScala in 2018 Keynote | Rod JohnsonBut Java has pattern matching! | Alejandro Serrano MenaHosts: WebsiteBlueskyWebsiteBlueskyGuest: TwitterLinkedInTimeline: (0:00) Intro (0:52) The origins of Spring (6:40) You need a business model (8:21) Consistency is key (9:39) Sustainable open source (14:22) Parallels with JetBrains and Kotlin (15:29) Rod’s journey around the JVM (20:48) Shoulders of giants (22:34) The newcomer experience (24:40) LLMs write great Kotlin (30:34) “You can start without great pain” (33:32) Extension functions (36:15) Too much magic? (37:56) Rod’s feature wishlist (39:37) Versioning and compatibility (41:19) Ecosystems and interop (43:34) Kotlin type system evolution (46:27) Kotlin with Spring (52:24) Learning Spring with Kotlin (54:46) Kotlin in 5 years? (1:00:39) Rod’s current work (1:03:58) Wrap-up

Sebastian and Márton discuss building KMP libraries with Jay Shortway, the author of RevenueCat’s Kotlin Multiplatform SDK for in-app purchases. Resources:RevenueCat KMP SDKHow we built the RevenueCat SDK for Kotlin MultiplatformHybrid SDK Architecture at RevenueCatttypic/swift-klib-plugin on GitHubRevenueCat/purchases-kmp on GitHubConsider moving `Instant` and `Clock` to the standard library · Kotlin/kotlinx-datetimeRevenueCat openings Hosts:WebsiteBlueskyWebsiteBlueskyGuest:Twitter (0:00) Intro (0:44) What’s RevenueCat (4:00) In-app purchases are hard (7:22) The multiplatform SDK (12:44) The demand for KMP (16:30) Hiring and team structure (18:42) SDKs for any framework (21:27) Building on native SDKs (23:45) Improving iOS linking (24:54) The SDK is on GitHub (26:05) Benefits of building on native (28:18) Designing a common API (33:21) Add-on modules for SDKs (37:30) Instant in the standard library (38:04) Returning results from the API (39:53) API design decisions (44:57) Codegen opportunities (45:48) The best things about KMP (47:07) KMP improvements wishlist (48:28) The KMP journey (49:45) Wrap-up

Sebastian and Pamela discuss what it means to be an expert in Kotlin Multiplatform, with the help of a panel of experts! Learn about why it's interesting to dive deep into a certain technology, recommendations on how to learn advanced topics, and general advice on how to get the most out of using KMP. KMP libraries: Interesting code to explore by Jake Ecosystem wishlist Learning resources HexFormat and Uuid and More KMP experts Kevin Galligan Russell Wolf Jesse Wilson Sebastian Sellmair Salomon Brys Hosts: Sebastian Aigner Pamela Hill Guests: Jake Wharton John O'Reilly Konstantin Tskhovrebov Tadeas Kriz Timestamps: (0:00) Introductions (1:40) Why be a KMP expert? (9:14) First steps to being an expert (16:38) Respecting each platform (24:04) Libraries for KMP (27:45) Advanced learning resources (38:18) Ecosystem wishlist (43:03) Exercising your KMP skills (48:15) Shoutouts to other experts (51:34) Wrap-up

In a slightly unconventional episode, Sebastian and Márton talk to the founders of Skip, an iOS-to-Android, Swift-to-Kotlin transpiler solution. Marc and Abe have a background working on both Apple platforms and the JVM, and their latest project is a bridge across these two ecosystems. SkipSkip.tools on GitHubContributing to SkipUI webinarkdoctor Hosts: WebsiteBlueskyWebsiteBluesky Guests: TwitterMastodonGitHub (0:00) Weather (2:02) Introductions (3:10) ⁠Elevator pitch⁠ (3:45) The initial idea (6:14) Pivot around the server-side (8:35) Skip(.tools) (8:56) The target audience (9:58) What about Android devs? (12:11) The current state (14:57) Pricing and components (16:43) ⁠Contributing to SkipUI⁠ (18:55) Reimplementing everything (23:07) ⁠The Skip stack⁠ (26:17) Wrapping JVM types (28:27) Writing Kotlin in Swift?! (29:56) Tooling support (32:02) There’s a Gradle project! (34:39) iOS API coverage (38:24) Platform differences (40:10) Data storage (44:31) Building on JVM libraries (46:42) JSON problems (48:00) Testing the Skip stack (51:42) SwiftUI to Compose (58:21) IDE experiences (1:03:35) Conclusion

Sebastian introduces the new co-host of the podcast, in a special episode recorded on location at droidcon New York! Joined by Russell Wolf, author of the multiplatform-settings library, we discuss the conference, different code sharing approaches for Kotlin Multiplatform, and how to build great multiplatform libraries. When sharing isn’t caring: Using platform-specific code in Kotlin MultiplatformCompose Multiplatform on iOS: On the Road to StableComposing an API the *right* wayAccompanist WebView implementationrusshwolf/multiplatform-settings on GitHubRoomSQLDelightKoinKotlin-injectViewModel Hosts: WebsiteWebsite Guest: GitHubTwitter Timestamps 0:00 Intro at home 2:02 Intro at droidcon NYC 4:23 Russell’s talk topic 8:14 Code sharing approaches 12:28 Wrapping native APIs 16:18 Attempted segue 16:35 Designing reusable APIs 18:02 Actual segue 18:14 multiplatform-settings 20:23 Supported platforms 24:05 SharedPreferences challenges 26:20 Observable preferences 29:51 Secure storage 30:55 Windows again 31:36 Library code as reference 33:15 Testable library code 35:05 Initializing a KMP library 38:18 Database libraries 40:55 Dependency injection 44:40 Outro

In this episode, we talk about the future of Kotlin and its development after the 2.0 version.

In this episode of Talking Kotlin, Hadi Hariri and Sebastian Aigner chat with Raphael Michel, the founder of pretix, an open-source ticketing system. Raphael shares his fascinating journey, from building pretix to solve a conference ticketing problem to becoming a full-fledged company with a global reach. The conversation dives into the complexities of event ticketing, the challenges of the pandemic, and the surprising new markets pretix entered, like managing access for public swimming pools in Berlin. Throughout the episode, Raphael discusses how Kotlin plays a crucial role in pretix's development. He talks about using Kotlin for various components, including Android apps, desktop applications, server-side logic, and even future plans for integrating with hardware like turnstiles.

Join us for an in-depth conversation with Michael Rittmeister and Luca Kellermann, the brains behind Kord, a Kotlin library designed for interacting with the Discord API. In this episode, we dive into the complexities of the Discord API, the importance of WebSockets, and the challenges and strategies in building and maintaining a modularized library. We also explore the future of Kord, including their move towards native support and the ongoing effort to keep up with Discord's evolving features. Whether you're a Kotlin enthusiast or a Discord bot developer, this episode is packed with valuable insights and practical advice. Kord library – https://github.com/kordlib/kord Michael on X – @SchlaumeierTVDE Luca on GitHub – https://github.com/lukellmann

🚀 Dive into the Compose multiverse with the latest episode of Talking Kotlin! 🌐 In this insightful conversation, our hosts, Seb and Hadi, bring on a special guest, Adriel Café, to discuss two powerful libraries in the Kotlin ecosystem – Lyricist and Voyager. 🎼 Lyricist: The Missing Piece of Jetpack Compose Adriel shares the journey behind Lyricist, an open-source library designed to simplify UI development with Jetpack Compose. Discover how Lyricist leverages sealed classes to enhance navigation, making it an indispensable tool for Compose-based Android apps. 🌍 Voyager: Compose on Warp Speed Get ready for a warp-speed adventure with Voyager! Adriel introduces Voyager, a navigation library for Compose Multiplatform, inspired by Star Trek's Voyager ship. Learn how Voyager simplifies navigation across Android, iOS, desktop, and even the web, supporting Compose Multiplatform projects seamlessly. 🤖 Lifecycle Challenges and Stability in Voyager Adriel delves into the challenges of handling lifecycles in Android and how Voyager tackles them. Discover the complexities, experimental APIs, and ongoing efforts to stabilize Voyager for a robust and crash-free navigation experience. 🛠️ Contributing to Open Source and Community Support The trio discusses the importance of open-source contributions, community support, and the fascinating world of Compose Multiplatform. Explore the nuances of transitioning from Android to Compose Multiplatform, and get a closer look at the exciting projects Adriel has been working on. 📚 Resources and Links Mentioned Lyricist: https://github.com/adrielcafe/lyricist Voyager: https://voyager.adriel.cafe/ Adriel's GitHub: https://github.com/adrielcafe Follow Adriel on Twitter: https://twitter.com/adrielcafe 👍 Enjoyed the episode? Don't forget to like, share, and subscribe! Let us know your thoughts in the comments below. Have a Kotlin-related topic you'd like us to cover in a future episode? Share your suggestions and join the Kotlin conversation!

🚀 Immerse yourself in the world of Kotlin as the latest podcast episode unveils the inner workings of the Kotlin Foundation! 🎙️ Join Sebastian and Hadi and a stellar lineup of guests, including Ksenia Shneyveys, Trisha Gee, Kevin Galligan, Charles Anderson, and Jeffrey van Gogh, as they share exclusive insights into the foundation's mission, projects, and plans for the future. 🌐 Discover the foundation's inception, core objectives, and impactful collaborations between founding members JetBrains and Google. Gain a deeper understanding of Kotlin's significance in the tech landscape and explore how the foundation is shaping the language's evolution. 🔍 Dive into the intricate workings of the Kotlin Education Committee. Explore their mission to foster the next generation of developers through initiatives like the Google Summer of Code and the Kotlin Multiplatform Contest. Uncover how Kotlin is making its mark in academia, with top universities adopting it as the go-to language for introductory computer science courses. 💼 Hear from representatives of new foundation members, Gradle, Shopify, and Touchlab. Kevin, Charles, and Trisha share valuable perspectives on why their companies joined the Kotlin Foundation and how they contribute to the thriving Kotlin ecosystem. Discover the benefits of membership and how these organizations are actively shaping the future of Kotlin. 💡 Whether you're a seasoned Kotlin developer or just stepping into the world of programming, this podcast episode offers a unique glimpse into the heart of the Kotlin Foundation. Don't miss the chance to stay updated on the latest developments, initiatives, and opportunities within the Kotlin community! 🚀 Like, share, and subscribe to stay connected with the Kotlin community and unlock the full potential of this powerful programming language! The Kotlin Foundation Annual Report 2023 – https://kotl.in/kfr_2023 Kotlin Foundation – https://kotlinfoundation.org/ #KotlinFoundation #Programming #TechPodcast #KotlinCommunity #Google #JetBrains #Gradle #Shopify #Touchlab #KotlinPodcast

Join us in this exciting episode of Talking Kotlin as we dive into the world of Kotlin Multiplatform with three special guests, Mike Nakhimovich, Yigit Boyar, and Matthew Ramotar, the minds behind the popular library 'Store' — a Kotlin Multiplatform library for building network-resilient applications. We explore the journey of 'Store' from its earlier versions to the recently released Store 5, shedding light on the challenges faced in making the library multiplatform. The conversation touches on various topics, from the adoption of Kotlin Multiplatform in different use cases, the integration with other Kotlin ecosystem tools like Molecule, to the challenges and goals ahead for 'Store.' Whether you're an Android developer, Kotlin enthusiast, or just curious about the latest developments in the Kotlin ecosystem, this episode offers valuable insights and a glimpse into the future of Kotlin Multiplatform development.

Welcome to another engaging episode of Talking Kotlin! In this edition, we dive into the dynamic world of Android development with Colin White, the creator of the widely acclaimed Coil library. Join us as we discuss the latest developments, insights, and the exciting roadmap for Coil. 🚀 Highlights from this Episode: Learn about Colin's journey in developing the Coil library. Discover the pivotal role Coil plays in simplifying image loading for Android developers. Get an exclusive sneak peek into the upcoming Coil 3.0, featuring multi-platform support and seamless integration with Jetpack Compose. 🔗 Helpful Links: Coil Library GitHub: github.com/coilkt/coil Follow Colin White on Twitter: @colinwhi 🌐 Connect with the Kotlin Community: https://kotlinlang.org/community/ Kotlin Foundation: https://kotlinfoundation.org/

Dive into the intricate world of microservices with the latest episode of Talking Kotlin, hosted by Sebastian and Hadi . In this engaging conversation, the hosts are joined by Ivan and David, the masterminds behind HTTP4K, to discuss the nuances of simplicity in software development and the often-misunderstood landscape of microservices. The episode kicks off with a discussion about the deceptive allure of complexity in building software. Ivan and David share insights into their roles as consultants, shedding light on the misconception that complexity is synonymous with efficiency. They challenge the industry norm and question whether microservices have become overly complex without a clear reason. As the discussion progresses, the hosts inquire about the scalability and applicability of HTTP4K. Ivan and David emphasize the simplicity of HTTP4K and its efficacy, providing valuable insights into its application in various scenarios. They discuss the importance of understanding application growth and the potential challenges that may arise, such as the need for databases, queues, and caches. At the end, the conversation steers towards structuring applications and the patterns recommended by Ivan and David. They address the significance of mono repos and multi-service testing, highlighting the need for understanding how to construct larger applications. Join the hosts and guests in this thought-provoking episode as they demystify the complexities of microservices and celebrate the elegance of simplicity in software development. Whether you're a seasoned developer or just stepping into the world of microservices, this episode provides valuable insights and a fresh perspective on building robust and scalable software. For more Kotlin insights and exciting discussions, don't miss Talking Kotlin. Subscribe now and stay tuned for upcoming episodes!

In this episode, we talk to Rick Clephas, one of the Kotlin Foundation Grants Program winners and the creator of KMP-NativeCoroutines and KMM-ViewModel. Rick shares how the KMP-NativeCoroutines library came into existence, how it works, and the challenges he faced during its development. We’ve also discussed Rick’s motivation to apply for the grant and how it helps him allocate more time and resources to the project. And finally, watch this episode to see how we reached the decision to rename the KMM-ViewModel library to KMP-ViewModel and the reason behind it. The Kotlin Foundation Grants Program winners: https://kotl.in/j8dckl KMP-NativeCoroutines: https://github.com/rickclephas/KMP-NativeCoroutines KMM-ViewModel: https://github.com/rickclephas/KMM-ViewModel

In this episode, we are talking to engineers from @instaboxglobal who use Compose Multiplatform in Production.