Advent of Code 2025: A Kotlin Playground

Ksenia Shneyveys

Join us live for five days of Advent of Code puzzles and five Kotlin livestreams on December 1–5. Solve the puzzles in Kotlin with help from Kotlin team experts and fun community guests, climb the leaderboard, learn new tricks, and have a chance to win some prizes along the way!

Here’s what we have planned for 2025:

• From December 1–5, join daily livestreams with Sebastian Aigner, Kotlin Developer Advocate, and special guests as they explore solutions and share Kotlin tips.
• Hang out with the supportive Kotlin community in Kotlinlang Slack, where people post hints, discuss approaches, and learn from one another.
• Take part in our Kotlin leaderboards for a chance to win exclusive prizes – both for top performers and for active community members who share their Kotlin solutions.

Join us for this JetBrains festive tradition and try solving our Kotlin puzzles this year!

If you enjoy a bit of friendly competition, you can participate in our Kotlin leaderboards on adventofcode.com.

We’ll have exclusive prizes for top performers and extra rewards for randomly selected participants who share their solutions on GitHub using the aoc-2025-in-kotlin topic.

Go to the Leaderboard section of your Advent of Code profile and enter one of the invite codes below:

• Leaderboard 1: 2343137-c975ff11
• Leaderboard 2: 2553918-98f6b5ed
• Leaderboard 3: 2076885-6961eed5

Some handy resources to get you started:

• The Kotlin Advent of Code GitHub template and instructions on how to use it.
• Solutions from previous years in idiomatic Kotlin.

Want to be in the running for exclusive Advent of Code in Kotlin prizes? Here’s what you need to do:

1. Solve at least three Advent of Code 2025 puzzles using Kotlin.
2. Publish your solutions on GitHub in a repository and add the topic aoc-2025-in-kotlin by:

• Opening your repository on GitHub.
• Clicking the gear icon (⚙️) in the top right-hand corner of the repository page.
• Adding aoc-2025-in-kotlin in the Topics field.

3. Make sure we can contact you via your GitHub profile by including an email address, X handle, or Bluesky username.

This helps us discover your solutions and include you in the prize draw!

Join us for Advent of Code!

We’re excited to spend another Advent season solving puzzles, exploring Kotlin, and celebrating clever solutions together.

Happy coding, and see you at Advent of Code in Kotlin!

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