How it works

Every day from 18 October for 24 days, a new door opens at 20:00 Europe/Sofia. Behind it: a small hacking challenge. Find the flag (it looks like AOC{...}), submit it, collect a star and a puzzle piece. Challenges start gentle and get a bit spicier towards Christmas. 🌶️

Scoring: points melt like snow

A challenge is worth its full points the moment it opens. Every minute after that it loses a little, linearly, until it's worth 10% after 24 hours — and it stays at 10% forever after. Late solves always count!

Solved after	Points (of 100)
instantly	100
1 hour	96
6 hours	78
12 hours	55
18 hours	33
24 hours+	10

Formula: points = base × max(10%, 1 − 0.9 × minutes_since_release / 1440), frozen at the moment you solve. Ties are broken by who reached the score first.

Badges & titles

🍪Cookie CrumbsSolve your first challenge.

🩸First BloodBe the very first to solve a challenge.

🐦Early BirdSolve a challenge within 15 minutes of release.

⚡Sleigh SpeedSolve a challenge within 1 hour of release.

🦉Night OwlSolve something between 02:00 and 05:00.

🔥Warm FireComplete 3 days in a row on their release day.

🪵Yule LogComplete 7 days in a row on their release day.

🎶Twelve DaysComplete 12 days in a row on their release day.

⛓️Unbroken ChainComplete every day on its release day.

🎁Week 1 WrappedComplete days 1–7.

🎀Week 2 WrappedComplete days 8–14.

📦Week 3 WrappedComplete days 15–21.

🛷Final StretchComplete the last days (22+).

🧭Better Late Than NeverSolve a challenge 3+ days after release.

🎅Christmas EveComplete the final day before midnight.

🎄Full AdventComplete every single day.

🧩Puzzle MasterPlace every piece of the jigsaw.

Titles grow with your stars: Snowflake → Elf Intern (1+) → Toy Hacker (4+) → Reindeer Ranger (8+) → Head Elf (14+) → Sleigh Pilot (20+) → Santa's Root (24+).

A streak counts consecutive days you completed within 24 h of release.

Instances

Some challenges need a live server. Hit Launch instance on the challenge page and you get your very own container for a while (you can extend it). One instance at a time, please — stop it when you're done. 🛑

Rules

Play solo. Talking about techniques after a day's 24 h window is great; sharing flags or solutions before is not.
Flags and handouts are personalised. Submitting someone else's flag is detected and will get you on the naughty list.
Only attack the challenges — not the platform, the Discord, the infrastructure, or other players.
No brute-forcing the flag form. If a challenge seems broken, ping the organisers on Discord.
Be kind. Help beginners. Have fun. 🎄