handbook.academy · an open library
Engineering handbooks,taught the way you'd want to learn.
Single voice. Plain prose. Living docs. Free, open-source, no sign-up — 365 chapters across 3 books, with 1 more on the way.
- Live
The HLD Handbook
System design, done right
- Chapters
- 159
- Words
- ~583K
- Beta
The DSA Handbook
Algorithms, taught right
- Chapters
- 120
- Words
- ~278K
- 2026 · planning
The LLD Handbook
Object-oriented design, patterns, refactoring, and testing — for engineers who already write code professionally.
In writing - Beta
The AI Engineering Handbook
Production AI, done right
- Chapters
- 86
- Words
- ~171K
What makes it different.
Three rules the whole library follows. They’re also why everything stays free.
Free, forever.
CC BY-SA 4.0 content. MIT code. No paywall, no ads, no email gate, no “sign in to continue.”
One author, one voice.
No CMS, no committee, no SEO copy. Every chapter reads like the same person taught it — because they did.
Living docs.
Updated when the truth changes. Mistakes get fixed. Every page carries a
date_updatedyou can audit.
Pick a book. Start reading.
All 3 live books open immediately — no account, no setup.
Watching the LLD handbook? Star the repo and you’ll know when it ships.