This is a book by Alex Xu. My notes are from a borrowed physical copy. These are the chapters: System Design Ch 1 System Design Ch 3 System Design ch 4 - Rate Limiter System Design ch 5 - Consistent Hashing System Design ch 6 - Key Value store System Design ch 7 - Unique ID generator System Design ch 8 - URL Shortener System Design ch 9 - Web Crawler System Design Ch 10 - Notification System