Netflix Software Engineer Interview Experience — First-Ever System Design Round, a Subscription System, and an Offer

This was my very first system design interview, and I had no real background in it at all.

I had about a week to prepare.

I began with an online system design course and read all of its articles. They explained what system design even is and gave me an outline I could stick to.

After that I moved on to the course's practice problems, and those are what really changed things for me.

I watched some videos as well, but to be honest they barely helped. You listen, each step seems sensible, and you still can't tell whether you could do it yourself, since nobody gives you any feedback.

Things that helped:

• getting familiar with the main building blocks (databases, caches, queues, load balancers)
• understanding the recurring trouble spots, such as scaling and trade-offs
• solving problems myself rather than just watching someone else do it

Early on it was chaotic and every result came back red :( Once I had done a few of them, though, it all started clicking.

The interview process matched what Netflix is famous for, so nothing surprised me.

In the system design round, the prompt was to design a subscription system for Netflix.

The discussion covered:

• what a subscription involves
• charging customers
• moving between plans, up or down
• retrying failed payments
• what happens as the system grows

It came across as a genuine conversation, not a trick question. All they were after was seeing how I think. I also feel that keeping the mood light and tossing in a joke now and then got the interviewers to relax.

What worked and what didn't

Worked for me:

• keeping the design simple
• sticking to the fundamentals
• talking my answers through out loud
• doing problems set up like a real interview

Didn't work for me:

• sitting back and absorbing material
• watching videos without trying anything on my own

Advice

For a first system design interview, my advice is not to overthink it. Concentrate on:

• getting the basic building blocks down
• picking up a handful of common patterns
• doing as many practice runs as you can

If you can, find a partner and put a timer on. It's uncomfortable in the beginning, but it pays off.

Honestly, working through the practice problems was the most valuable piece of my prep.