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The hard stuff, made simple

210 lessons across 12 topics. Every lesson gives you an everyday example, a code editor you can run, and the exact result to expect. Search or browse, then open one.

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Code foundations

Data & the web

Design at scale

Data & AI

Ship & measure

The hard stuff, made simple

Programming BasicsThe very first building blocks — the words and rules every program is made of.0/1313 lessons+

Data StructuresHow to hold your data — the containers you put information in.0/2727 lessons+

AlgorithmsHow to work with your data — step-by-step recipes to get things done.0/3636 lessons+

DatabasesHow apps remember things — storing, finding, and organizing data that lasts.0/1212 lessons+

Web & InternetHow the web actually works — what happens between your click and the page.0/1212 lessons+

Design PatternsHow to organize big code — proven blueprints for common problems.0/2626 lessons+

System DesignHow to build big systems that stay fast and reliable as they grow.0/1717 lessons+

CloudHow real apps run on rented computers — scaling, staying up, and shipping safely.0/1616 lessons+

Data ScienceHow to find the story hidden in data — the math behind the charts.0/1818 lessons+

Generative AIHow AI that writes, answers, and creates actually works underneath.0/1717 lessons+

Testing & QAHow we prove code works and keep it working — the safety net under every change.0/1010 lessons+

ProductHow teams decide what to build and measure whether it actually worked.0/66 lessons+