Complex concepts, dissected.
Step by step breakdowns of system design, networking, and security — built for engineers who want to actually understand how things work.
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Pick a track and work through lessons in order.
AI
Understand how large language models work, how to build with them, and how to ship AI features safely.
12 lessons
Cloud
Master cloud infrastructure — from virtual machines and containers to Kubernetes and multi-region architecture.
23 lessons
Networking
Understand the protocols and infrastructure that power the internet, from DNS to TCP/IP.
12 lessons
Security
Explore encryption, authentication, and the techniques that keep systems safe.
15 lessons
System Design
Learn how to design scalable, reliable systems — from load balancers to distributed databases.
29 lessons
Latest lessons
Recently published across all categories.
The OSI Model
The seven layer framework that defines how data travels through a network. Essential context for understanding every networking concept.
TCP vs UDP
Two ways to send data across a network — one reliable and ordered, one fast and fire-and-forget.
The CIA Triad
The three properties every security decision trades against — confidentiality, integrity, and availability.