After reading a chapter (e.g., "Design a Key-Value Store"), open a blank whiteboard canvas. Try to reconstruct the architecture from scratch using your own words and logic.

Alex walked out of the building feeling light. He hadn't been perfect, but he had been better . He hadn't let the PDFs wash over him passively; he had forced the knowledge to fit a framework in his head.

: The books contain over 400 diagrams across both volumes, making complex concepts like consistent hashing, rate limiting, and database sharding much easier to digest.

Alex Xu doesn't just give you answers; he gives you a process. Every chapter follows the same rigid, repeatable structure:

Vertical vs. horizontal scaling, load balancers, and database replication. Designing a unique ID generator in a distributed system. Architecture for a URL shortener (TinyURL clone). Designing a web crawler and a notification system. Volume 2: Advanced Topics

Alex Xu has released two primary volumes, each targeting different levels of engineering expertise. Volume 1: The Foundations

: Covers specialized systems like proximity services , digital payment systems , stock exchanges, and real-time collaboration apps. Visuals : Includes over 300 detailed architectural diagrams.

But then came the hard part. How do you actually apply that to designing Instagram?

: Instead of diving straight into diagrams, the book teaches a consistent strategy for every problem: Understand the problem and design scope. Propose a high-level design and get buy-in. Conduct a deep dive into specific components. Wrap up with improvements and trade-offs.

: Sketch the end-to-end flow. Connect the client, load balancer, API gateway, application servers, and databases.

Here is a breakdown of why Alex Xu's PDF is "better" for the vast majority of candidates.

Owning the PDF does nothing if you don't use it correctly. Here is the "Better" method to beat the interview.