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Kotlin

Concise. Multiplatform. Fun.

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Code examples
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")
    }
}
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Kotlin,
Built for the AI Era

Null safety and concise syntax already make Kotlin a language AI gets right.
We’re making it even better with open benchmarks and agent-ready tooling.

Latest news

Signatures, be true: domain errors and functional handling in Kotlin

August 19, 2026

Signatures, be true: domain errors and functional handling in Kotlin

Here’s a function that signs a document: In Kotlin, Unit means the function completes without returning a meaningful value – roughly equivalent to void in Java. Got it? Now, tell me what could go wrong. You can’t.  Yet, the code might be invalid. The signing window might have closed. The database might be down. The […]

Klibs.io Grows to 4,200+ KMP Projects With Smarter Discovery and New AI Integrations

August 17, 2026

Klibs.io Grows to 4,200+ KMP Projects With Smarter Discovery and New AI Integrations

Explore a growing Kotlin Multiplatform catalog in your browser, or bring up-to-date library data directly into your AI development workflow through the klibs.io MCP server. When we introduced klibs.io in December 2024, the goal was simple: make it easier to find a Kotlin Multiplatform library that fits both your use case and target platforms. Since […]

Exploring Compose HTML for Server Side Rendering

August 14, 2026

Exploring Compose HTML for Server Side Rendering

Something is happening in server-rendered web development. React shipped Server Components. HTMX made “hypermedia” cool again. Phoenix LiveView proved a server can push interactive UI updates without a client framework in sight. Every ecosystem seems to be rediscovering the server as a place to render UI, except one: the JVM. What if Compose, the UI […]

When Escape Routes Become Toll Roads: Mapping How Developers Move Between Programming Languages

August 12, 2026

When Escape Routes Become Toll Roads: Mapping How Developers Move Between Programming Languages

TL;DR: This post relates findings about language migration from the 2025 State of Developer Ecosystem survey. In general, project requirements are still the most common reasons for switching languages. One outlier from this trend, however, is Kotlin. People switch to Kotlin not because they have to; they switch because it simply feels better to work […]

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Share code on your terms and for different platforms

Simplify the development of cross-platform projects with Kotlin Multiplatform. It reduces time spent writing and maintaining the same code for different platforms while retaining the flexibility and benefits of native programming. Kotlin applications will work on different operating systems, such as iOS, Android, macOS, Windows, Linux, watchOS, and others.
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Big, friendly and helpful community

Kotlin has great support and many contributors in its fast-growing global community. Enjoy the benefits of a rich ecosystem with a wide range of community libraries. Help is never far away — consult extensive community resources or ask the Kotlin team directly.

Kotlin Foundation

Actively supports community efforts in developing the Kotlin ecosystem.

Start using Kotlin today!