For the system design interview
Watch Instagram grow from 5K to 1B users — and fix what breaks
The design round asks you to grow a system and defend every choice. Practise exactly that: turn the traffic up on a real system, see which part gives out first, and fix it. Then design against a brief on a canvas and get it marked — the same design gets the same score every time, with the reason behind every requirement.
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Scale journey · Instagram
Stage 1 of 6
Comfortable here.
Drag the traffic up and watch what gives way first.
Single point of failure · EC2
One server takes every request. Now fix it — what do you add?
Fixed on the first try — stage 2 unlocked
A load balancer spreads the load across servers. Next wall: ~100K users.
New · Real-world system design
5 real systems, from one server to billions
See how Instagram, Netflix, Uber, Twitter and WhatsApp grew from one server to billions of users. Turn the traffic up, watch a service buckle, fix it — then build the architecture yourself.
Explore scale journeys →Or just read how each one scaled
Why not just ask ChatGPT?
A chatbot and a whiteboard are free, and good for plenty. For interview prep, three things they do not do:
The same design gets the same score
Ask a chatbot to mark a design twice and you can get two verdicts. Here a scorer marks it against what the brief requires, the same way every time, so a score means something next week too. The AI writes the review; it never sets the number.
Load you can turn up
A chat can tell you what breaks at a million users. Here you drag the traffic up on Instagram, Netflix, Uber, Twitter and WhatsApp, watch which part gives out first, and fix it on the canvas.
A course, not a blank box
40 AWS scenarios written the way an exam writes them, and every attempt kept — so you can see which kind of design you keep losing marks on.
Choose your track
Two kinds of design round, one canvas and the same marking. Google Cloud and Azure are on the way.