A plan instead of a blank stare
There's no single right answer — press ⌥↩ and Hint lays out the structure: requirements, load, components, bottlenecks. You flesh out every step in your own words.
Use case
System design interview: the answer framework is on screen before you start talking
"Design a news feed." The question is wide open — and that's the whole test. Vizir hears the task and instantly lays out the skeleton: requirements → load estimates → components → bottlenecks. You drive the reasoning out loud, in your own words, while the overlay keeps the plan in view and picks up every follow-up. That's system design help at the exact moment you need it.
What it looks like
A play-by-play example
Here's a typical exchange: an open-ended design task, a skeleton in Hint, and a follow-up about scale.
InterviewerDesign a news feed — think a social network. Where do you start?
VizirHint → “I'd start with requirements: how many active users, and is it read-heavy or write-heavy. I'll estimate the load in requests per second, then lay out components — a load balancer, a cache, a sharded database, and a queue to deliver posts to followers. And I'll flag the bottlenecks up front.”
YouRequirements and load first, then I'll lay out the components and call out the bottlenecks.
InterviewerSay 50 million daily actives. How does your fan-out hold up at peak?
VizirHint → “I'd push writes through a queue to smooth the peaks. For accounts with millions of followers I'd switch from fan-out on write to building the feed on read, and keep hot feeds in cache — otherwise the queue backs up.”
YouBuffer writes with a queue, and for the big accounts build the feed on read plus cache the hot ones.
What Vizir does in this scenario
Your whiteboard goes into context
The interviewer shares a diagram or a requirements doc — grab it with ⌥C or send selected text with ⌥⇧C. From there, Vizir reasons about your system, not a generic one.
Scaling questions won't knock you off course
"What happens at 10× traffic?" Vizir hears the question straight from the call and suggests the next move: sharding, replicas, cache invalidation — no re-typing the problem.
Defend every choice
SQL vs NoSQL, push vs pull — when they ask "why this way?", ⌥↩ brings up the arguments on both sides. The decision is still yours — now you can back it up.
Quick questions
I've never done a design round before. Will this actually help?
Yes. The framework shows up before you start answering and walks you through requirements, load, components and bottlenecks. You don't have to hold the whole methodology in your head — just keep the conversation going.
Can Vizir read a diagram drawn in Miro or Excalidraw?
Yes. Screenshot it with ⌥C — the shot goes to the AI along with the conversation, and the hints build on your actual architecture.
What if the interviewer steers into something niche, like data consistency?
Vizir hears every turn of the call and keeps up: replication, quorums, CAP — whatever fits the direction the conversation just took.
Walk into your next design round with a plan
3 days and 30 minutes of speech free — no credit card required. Install Vizir ahead of time and run a practice round — the skeleton, the follow-ups, just like the real thing.