Netflix: What Happens When You Press Play?

by Todd Hoff

Most of us have used Netflix at one time or another. Who wouldn’t love peeking behind the curtain to learn the inner-secrets behind how Netflix works? If you're the curious type then this book is for you. And when I say book, it’s a short book. I kept it short on purpose. I want this book to be simple and straightforward. I explain everything in basic terms. I use a lot of pictures and examples. So don’t worry. Even if you aren’t a tech-wiz, you’ll be able to understand what’s going on. Here are the kind of things you’ll learn. Did you know • Stranger Things season 2 was shot in 8K, has nine episodes, took 190,000 CPU hours to encode, and is made up of 9,570 different video, audio, and text files? 
• Netflix plays more than 1 billion hours of video each week? 
• Netflix accounts for over 37% of peak internet traffic in the United States? 
• Netflix runs on several hundred thousand EC2 instances in Amazon’s cloud and can use as many as 300,000 CPUs at one time to encode video?
 • Netflix runs its own world-wide content delivery network (CDN) so it can deliver video to you the fastest and most reliable way possible? 
• Netflix predicts what you want watch tomorrow so it can cache video as close as possible to you today? 
• Netflix customizes your user interface based on learning your preferences? It’s possible the user interface you see isn’t the same user interface anyone else in the world will see. 
 If you don’t know what encoding means, or what a CDN is, or what caching is, or what cloud means, or what the internet is, or what EC2 is, or what an instance is, or how Netflix personalized itself for you—don’t worry, we’ll cover all that and much more. Sound fun? At the end you’ll have the immense pleasure of knowing exactly what’s going on the next time you press play on Netflix. Let’s get started!

67 pages, Kindle Edition

Published February 21, 2018

Reviews

[Bangara Raju · Rating 5 out of 5]

Well Explained

If some kid stops by and asked me what is email. I cannot explain.

Todd Hoff composed a beautiful tale to explain how Netflix works in a 60 page book, which can be understood by anyone.

Great book to read.

[Olha · Rating 5 out of 5]

I saw an ad for this book in Alex Xu's newsletter on system design, which mentioned that Netflix has its own CDN. My manager at a previous job talked about how dramatically resilient and fault-tolerant Netflix is to different failures, so I decided to read this book to identify my system design gaps.

The sections on S3, encoding, transcoding, and the client SDK were very clear. The part on Open Connect, OCA, ISP, and IXP was magical as always. When reading that Netflix places its CDN servers at ISPs' data centers, I wondered why ISPs would want this. I got the answer a few pages later. Which means the author addressed all potential questions for me 😃

Regarding resilience, I read that Netflix intentionally kills an entire availability region once a month to test the system in production.

[Verisimilitude · Rating 5 out of 5]

The whole complexities/algorithms of the Netflix system architecture condensed in a concise 60-page book.. Amazing.

[Kashish Mehta · Rating 5 out of 5]

Wow quick 60 pages beautifully explained even u know a bit about Netflix or layman superbly explained in this short read

[Dilbag Singh · Rating 3 out of 5]

Short book about how Netflix works.