Thank you to everyone who participated in Advent of Code 2025 in Kotlin! Once again, it was a joy to see so many of you sharing solutions, cheering each other on in Slack, and keeping the holiday codi

Kotlin is a modern programming language developed by JetBrains, designed to interoperate with Java and run on the Java Virtual Machine (JVM). With features like null safety, type inference, and extension functions, Kotlin offers a concise and expressive syntax for building robust and scalable applications. Developers can learn Kotlin's language features, explore its ecosystem of libraries and frameworks, and leverage Kotlin for developing Android apps, server-side applications, and multi-platform projects.

Kotlin

JetBrains wrapped up Advent of Code 2025 with Kotlin-focused participation, featuring five days of livestreams with Sebastian Aigner solving puzzles live. Nine winners were announced across three categories: Fastest to Solve (top leaderboard performers), Random (lottery-style selection), and Community (recognizing active helpers in the Kotlin Slack channel). The puzzles remain available year-round, with resources including YouTube recordings, previous years' solutions, and Kotlin Notebooks tutorials for continued learning.

Advent of Code 2025 in Kotlin: Puzzles, Prizes, and Community