AdventJS
Free December coding challenges in JavaScript, TypeScript or Python
AdventJS is a free coding calendar with one new challenge each day from 1 to 24 December. You solve each problem in JavaScript, TypeScript or Python in an editor on the site, and your code runs against tests, some of them hidden.
Free · Browser · New puzzle daily · Beginner
About AdventJS
Each challenge is marked easy, medium or hard. Your score depends on things like code complexity and speed, not on how many lines you write, and you can send new solutions to raise your score. This makes it good practice for clean, efficient code.
It suits beginners and intermediate programmers. The site is available in English and Spanish, and past editions can be chosen from a menu.
On Breakpoint since 23 Oct 2026.