An AI copilot for system design interviews

A system design round is a long conversation, and it's easy to lose your structure halfway through. GhostCue listens to the call and gives you an outline to talk around while you keep talking to the interviewer.

What you see after "design a rate limiter"

Press Answer when they finish the question. The card opens with one sentence you can say straight away, naming the main decision and why. Under it are short talking points, not a script:

• Clarify: the scope to focus on, what to leave out, and what matters most.
• Estimate: your assumptions and the one figure they lead to.
• Design: the parts of the system and how they fit.
• Trade-offs: what the design gives up, and why that's acceptable.
• Deep-dive: the hardest parts of this particular system.

Estimates are worked out from assumptions, not measured, so say them as assumptions and check the arithmetic before you lean on it.

When they change the requirements

Interviewers usually narrow in: "what happens when traffic doubles overnight?" Press Answer again. A follow-up asked straight away can join the same card, with the earlier answer folded to one line you can reopen. Otherwise it gets a card of its own. If the prompt is written in a shared document, press Screenshot instead. It reads the text on your display, so it won't follow a drawing on a whiteboard.

Auto answer is on at first, so an answer can appear without a press. Switch it off with the Auto switch on the bar.

Bring your own experience

Upload your résumé and the job description in the dashboard, and answers can draw on the systems you've really worked on. Use the card as prompts and say it your way.

Screen sharing

GhostCue asks your computer to keep the bar out of screen shares and recordings. Most meeting and recording apps respect that, but not all of them, and not on all systems. Check yours before a real interview.

Try it

GhostCue runs on macOS 13+ and Windows 10/11, and you start with 10 free trial sessions of 10 minutes (3 until you verify your email). Download GhostCue or read how answering works.