This year, we kicked things off with five days of livestreams on December 1–5, with Sebastian Aigner and fantastic guests solving puzzles live, discussing strategies, and showing off idiomatic Kotlin approaches.
If you missed the streams or want to revisit a clever trick, you can still catch up with the recordings:
The Advent of Code puzzles remain available all year round, and so does the community energy. The #advent-of-code channel in the Kotlinlang Slack was once again full of:
- Creative Kotlin snippets
- Non-spoiler hints
- Lots of encouragement
Whether you took part in discussions every day or just lurked and learned, thank you for making the channel such a friendly, collaborative space.
As in previous years, we invited you to solve Advent of Code puzzles in Kotlin, join our Kotlin leaderboards, and share your solutions on GitHub with the aoc-2025-in-kotlin topic for a chance to win special Kotlin prizes.
This year, we’re celebrating nine winners across three categories: Fastest to Solve, Random, and Community.
Fastest to Solve
These three contestants topped the combined Kotlin leaderboards, consistently solving the puzzles at impressive speed:
Congratulations on those lightning-fast stars and Kotlin-powered solutions!
Random winners
To give everyone a chance regardless of speed, we also randomly selected three prize winners from all the participants:
If you see your name here, keep an eye on your inbox. We’ll be in touch about your prize soon.
Community winners
Finally, Advent of Code in Kotlin wouldn’t be the same without the people who answer questions, share insights and alternative solutions, help newcomers get started, and keep the #advent-of-code channel buzzing throughout December.
This year, we’d like to give a special shout-out to these three community stars:
Thank you for your team spirit in the Kotlin community!
Advent of Code might be over for this year, but the puzzles and the learning opportunities remain. If you’d like to keep sharpening your skills and prepare for future events, here are some resources:
- Advent of Code 2025 in Kotlin YouTube playlist.
- Solutions to Advent of Code puzzles from previous years in idiomatic Kotlin.
- A tutorial on how to explore and solve programming puzzles using Kotlin Notebooks.
We want to say a huge thank-you, as always, to Eric Wastl and the Advent of Code team for creating such a beloved set of puzzles year after year.
Let’s keep exploring Kotlin, solving algorithmic challenges, and supporting each other. We hope to see you for the next Advent of Code in Kotlin! 🎄