Hey Product Hunt! 👋 I built BuildTheSystem because I noticed something about system design interviews: the hardest part isn't knowing the concepts — it's talking and drawing at the same time, under pressure, while someone watches. You can read all the books and watch all the videos, but nothing prepares you for narrating your thinking out loud while sketching a load balancer. So I built a mock interviewer that does what a real one does: 🎙️ It listens while you think out loud — and actually waits when you're drawing instead of talking over you 🧩 You draw with a typed palette (load balancer, Postgres, Kafka), so every component is structured data — no messy sketch recognition guessing at your boxes ⚡ It reacts to your diagram in real time. Connect a client straight to your database? You'll get asked about it the moment you draw the line — just like a real interviewer would. This is the practice tool I wish I'd had before my own interviews. I'd love to hear what you think especially from anyone prepping for interviews right now. What would make this more useful for you? Happy to answer any questions in the comments all day. 🙌 try it here: https://buildthesystem.xyz

BuildTheSystem

Design a System that can talk to you

Design a System that can talk to you