codecrafters-io/build-your-own-x
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The "build it yourself" approach to learning: recreate classic technologies — databases, operating systems, compilers, search engines — from scratch. One of the most-starred repos on GitHub.
The "build it yourself" approach to learning: recreate classic technologies — databases, operating systems, compilers, search engines — from scratch. One of the most-starred repos on GitHub.
A free programming books encyclopedia: an index of thousands of free ebooks and courses in hundreds of languages — a treasure trove for self-learners and developers.
A personal AI assistant that runs entirely on your device: connects 50+ apps (WeChat, WhatsApp, Slack, Telegram…), browses and fills in forms, runs commands, controls your smart home, and can even teach itself new skills. The fastest-growing open-source project of 2026.
A "superpowers" skill pack for AI coding agents: debugging playbooks, planning flows, testing strategies and more — so agents genuinely work the way experienced engineers do.
A performance-optimization system for AI agents: gives coding agents like Claude Code and Codex skills, instincts, memory and safety guardrails — like installing an operating system on your agent.