Kotlin
Concise. Multiplatform. Fun.
fun main() {
val name = "stranger" // Declare your first variable
println("Hi, $name!") // ...and use it!
print("Current count:")
for (i in 0..10) { // Loop over a range from 0 to 10
print(" $i")
}
}Kotlin
Concise. Multiplatform. Fun.
fun main() {
val name = "stranger" // Declare your first variable
println("Hi, $name!") // ...and use it!
print("Current count:")
for (i in 0..10) { // Loop over a range from 0 to 10
print(" $i")
}
}Kotlin
Concise. Multiplatform. Fun.
Multiplatform
Go cross‑platform without compromising performance, UX, or code quality.
AI development
Leverage AI models tailored for Kotlin, backed by JetBrains' open data, benchmarks, and tooling built into your workflow.
Backend
Build fast applications with Spring or Ktor. Kotlin's expressiveness makes backend code a pleasure to write and maintain.
Android
Write less boilerplate, ship more features with the official language of Android development since 2019.
Kotlin Tour
fun main() {
val name = "stranger" // Declare your first variable
println("Hi, $name!") // ...and use it!
print("Current count:")
for (i in 0..10) { // Loop over a range from 0 to 10
print(" $i")
}
}
Latest news
July 29, 2026
Secure Your APIs: OAuth2 and JWT for Beginners
This tutorial was written by an external contributor. APIs are frequent targets for bad actors since they expose data and functionality. Securing them while maintaining usability is often one of the most challenging and time-consuming parts of API development. OAuth 2.0 and JSON Web Tokens (JWT) help make these processes more manageable and reliable. They […]
July 28, 2026
KotlinLLM is Going Open Source
TL;DR KotlinLLM is now public. It’s a research prototype for delegating runtime logic to an LLM from Kotlin code. Instead of calling an LLM on every request or running a separate agent, you can write an explicit Kotlin call. Its body is generated Kotlin source code, and that code is updated as your application hits […]
July 17, 2026
Kotlin Turns 15: Celebrate the Kotlin Effect
🎉 Kotlin turns 15! 🎉 For 15 years, you’ve helped shape Kotlin into the language it is today. Whether you’ve built apps, contributed to the ecosystem, taught others, or simply chosen Kotlin for your next project – thank you for being part of the journey. Today, we’re celebrating Kotlin and the people who have made […]
July 9, 2026
The History of Kodee, Kotlin’s Mascot
A few years back, the Kotlin team figured it was time their programming language had a mascot – something fun and friendly to make developers feel more at home. After all, so many other programming languages have their own characters – Gofer, elePHPant, Dart’s Dash, or Rust’s Ferris, for example. Bringing Kodee to life wasn’t […]
fun main() {
val name = "stranger" // Declare your first variable
println("Hi, $name!") // ...and use it!
print("Current count:")
for (i in 0..10) { // Loop over a range from 0 to 10
print(" $i")
}
}Kotlin in action
Share code on your terms and for different platforms
Kotlin + AI
JetBrains is investing in AI models tailored for Kotlin, providing open data, benchmarks, and AI-native tooling integrated into your workflow.
At the same time, Kotlin makes it easy to build your own AI-powered features with seamless backend integrations and a growing ecosystem.
What you get with Kotlin + AI
- Strong support across JetBrains AI tools like AI Assistant and Junie
- Robust functionality for building AI-powered apps on the JVM
- Native integration with tools like Spring AI and LangChain4j
- Open data and benchmarks for better code generation
Build your own AI agents with Koog
Koog is JetBrains’ new Kotlin-native framework for creating powerful AI agents that run locally, interact with tools, and automate complex tasks. Whether you’re developing a simple chat assistant or an advanced multi-step workflow, Koog gives you full control with clean Kotlin code – no external services are required. Build, extend, and experiment with AI agents entirely in Kotlin.
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Kotlin Foundation
