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.
Consistency and Availability Tradeoffs
In distributed systems you can't have everything. Understanding the tradeoff between consistency and availability is fundamental to every design decision.
Proxies — Forward vs Reverse Proxy
Two types of proxies, two different jobs. Forward proxies protect clients, reverse proxies protect servers.
CDNs — Content Delivery Networks
How content gets delivered to users fast regardless of where they are in the world.