Last week at the KotlinConf 2026 keynote (watch the recording here), we announced Koog 1.0. Koog is JetBrains’ open-source framework for building AI agents in Kotlin and Java. It provides the core building blocks for agentic applications: tools, workflows, persistence, memory, observability, and integrations with existing JVM and Kotlin Multiplatform projects. We introduced Koog at […]
#kotlin
20 posts
27 May
20 May
Years of productivity-focused design are now visible in the data. Pragmatism has been central to Kotlin’s design from day one. The language prioritizes the developer’s convenience and productivity over academic purity or feature ambition. Developers describe working in Kotlin in a fairly consistent way: more time spent on what you’re trying to build, less time […]
15 May
We are updating the default project structure for Kotlin Multiplatform projects to give modules clearer responsibilities, better align with conventions used by other build systems and frameworks, and reflect the changes in Android Gradle Plugin 9.0. You’ll see this project structure in newly created projects generated by our tools, in the official documentation, and in […]
13 May
TL;DR New “val inside parentheses” syntax is being introduced to allow for name-based destructuring. Additionally, new syntax with square brackets is being introduced for positional destructuring. Both are currently Experimental (enabled using the -Xname-based-destructuring=only-syntax compiler argument) and will become Stable in a future release. In the distant future, the behavior of the “val outside parentheses” […]
2 Dec 2025
Expedia Group Technology — Engineering Exploring the strategy pattern and functional programming alternatives in Kotlin Photo by Karsten Winegeart on Unsplash When designing software around business processes (e.g., orchestration services), one of the key challenges is organizing business logic in a way that is maintainable, scalable, and adaptable to change. In this post, we’ll explore how to address such challenges…
6 Oct 2025
Photo by Mario Verduzco on Unsplash Medium Android App — Migrating from Apollo Kotlin 3 to 4: Lessons Learned In this post, I’ll share my experience migrating the Medium Android app from Apollo Kotlin version 3 to version 4, including the challenges I encountered and how I solved them to improve our GraphQL implementation. Understanding Our Apollo Cache Implementation Before…
26 Jun 2025
How Blinkit Cracked Android's Performance Puzzle with Droid Dex Adaptive real-time performance tuning — fewer ANRs, smoother UX, and smarter device-specific optimization Picture this: Your app runs buttery-smooth on Pixel 7 Pro while throwing ANRs on a Redmi Note 4. Users on a Fold 6 have to experience the same janky transitions as those on a ₹6,000 device. Sounds familiar?…
21 Feb 2024
Jetpack Compose both makes it easier and promotes usage of an internal design system by creating custom Compose components. But how should we build these components? In this article, we will take a look at possible implementations of a design component, explore their API verbosity and extensibility, and how we can find a balance between these characteristics to make Compose…
9 Feb 2024
During the development process, we often focus on the source code but rarely inspect the compiled bytecode. This means we’re missing out on a valuable source of information and data for analysis. How? Let’s delve into Dex file inspection and build a tool that demonstrates how source code changes impact the compiled binary. Have you ever set R8 rules to…
6 Sept 2023
Embarking on a journey Stepping out of SFO with the familiarity of the fogginess of the city, my story at Slack unfolds once again. As a return intern, I found myself prepped for another exciting summer, and this opportunity encompassed a renewed sense of anticipation — a mix between known pathways and new adventures. Returning…
8 Nov 2022
First and foremost, thanks for visiting my little slice of the internet! I hope the following is both insightful and comedic as I plan to @inject well constructed jokes throughout this post. Introduction Hello! My name is Aleksei and at the time of writing this I’m a rising Senior perusing a Bachelors of Science in Computer Science at the Rochester…
25 Oct 2022
About Me: Hey there! My name is Ryan, and I come from an unconventional background. I am not like most interns from the group in 2022. I’ve dropped out of college 3 times, worked in different fields for about 10 years, then transitioned into a bootcamp. Now working with Strava, they have set the expectation of what it should be…
10 Nov 2021
We use plenty of open source tools at Slack and we’ve benefited immensely from the wider Android, Kotlin, and Gradle communities. We also try to be good citizens by giving back. This includes things like sponsoring the Kotlin Lang Slack, contributions to projects we use like Anvil and Insetter, sharing projects of our own like…
20 Jul 2021
Note: This article assumes some familiarity with Dagger, Anvil, and Kotlin. We use Dagger heavily in the Slack Android app for compile-time dependency injection. It’s powerful, flexible, supports basic Kotlin idioms, and allows for advanced dependency injection patterns with less boilerplate. It’s not without its sharp edges though. It slows down our builds with kapt,…
15 Nov 2019
Background At RetailMeNot, we are excited by the promise of automating visual regression tests with Applitools . In this post, I’ll show how to make writing Applitools tests for Android a cinch. We’ll start with the official integration guide recommendations and then use JUnit and Kotlin features to make our tests concise and maintainable. This post assumes the reader is…
9 Jun 2017
It was hard to limit ourselves to 10 Nice Examples of Writing SQL in Kotlin With jOOQ, recently, because the Kotlin language has many nice little features that really help a lot when working with Java libraries. We’ve talked about the nice with() stdlib function, which allows to “import” a namespace for a local scope … Continue reading Using Kotlin’s…
18 May 2017
Kotlin is the next big thing. With Google announcing official support for Kotlin on Android, we’ll see a lot more traction for this lovely language. After today's #kotlin announcement, we're betting this tag will blow up just like Swift did. #io17. https://t.co/whOcJlJfWe pic.twitter.com/2QKEJIRYVi — Stack Overflow (@StackOverflow) May 17, 2017 We’ve already blogged about the … Continue reading 10 Nice…
31 Mar 2016
This article is overdue. After the hype around the release of Kotlin 1.0 has settled, let’s have a serious look at some Kotlin language features that we should have in Java as well. In this article, I’m not going to wish for unicorns. But there are some low hanging fruit (as far as I naively … Continue reading 10 Features…
15 Mar 2016
Here we go again. THAT TOPIC. But hang on. The approach discussed here (and in the Ceylon language) is not something you see every day. At the same time, it is very cunning. Nulls are baked into the language … or so it may seem. Indeed, in Ceylon, like in Kotlin (and possibly many other … Continue reading Ceylon Might…
22 Feb 2016
This has caught me by surprise. After studying the Kotlin language to learn about how to best leverage this interesting new language for jOOQ, I stumbled upon this puzzler. What do you think the following program will print? fun main(args: Array) { (1..5).forEach { if (it == 3) return print(it) } print("done") } Well… You … Continue reading A Very…