Free videos, articles and simulations on system design. Start with an interview question, or learn the basics first.
12 full system design problems, worked step by step.
Limit requests per user across many servers.
Turn long links into short ones and redirect billions of clicks.
Deliver messages to millions of connected users, including big groups.
Show each user the latest posts from the people they follow.
Send each alert once, through channels that can fail.
Track a million moving drivers and find the nearest one.
Fetch the web quickly without overloading any one site.
Stream the same videos to a huge audience at low cost.
Spread the load when one key gets most of the traffic.
Collect millions of data points a second and keep them for years.
Run tasks at the right time, out of hundreds of millions.
Count every ad click exactly once, even when events repeat.
Each part is an article. Most also have a video.
Six parts that build Java's garbage collectors from the ground up: what counts as garbage, how tracing reclaims it, why the heap is split into generations, how marking runs alongside your program, and how G1 and ZGC keep pauses short.
Some topics also have a simulation. Press Next and watch the system take one step.