Exercism

Advent of CodeAnnual programming puzzle competition. Runs every December.

Build Your Own XTutorials for rebuilding everything from Git to a database, from scratch.

Can I UseBrowser compatibility tables for every web feature. Essential for developers.

CodecademyInteractive coding lessons for beginners through intermediate developers.

CodePenBuild and share front-end code snippets. Great for inspiration.

Crafting InterpretersA beloved free book on building your own programming language, by hand.

CS50Harvard's famous intro to computer science. The best free CS course.

CSS Zen GardenThe same HTML, hundreds of different stylesheets. What CSS can do.

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