The system design interview that actually talks back.
Practice system design out loud with a senior AI interviewer. It talks, listens, and watches your whiteboard in real time — probing your design and coaching you when you're stuck — then hands you an honest scorecard. From your first round to senior loops.
One free session · no card required · backend, iOS & Android tracks.
Built for engineers with a real interview on the calendar
“Felt like the real thing — it caught me hand-waving over replication and wouldn't let it go.”
“The scorecard was more useful than three peer mocks. Specific, honest, actionable.”
“Talking out loud with something that sees my diagram fixed my pacing before the real interview.”
From cold start to honest feedback in one sitting
No setup, no scheduling, no awkward peer matching. Open a problem and start talking.
Pick a problem
Choose a preset system-design prompt for your track — backend, iOS, or Android — or bring your own.
Talk & sketch
The interviewer greets you out loud and runs a phased 45-minute session while you think aloud and draw on the whiteboard.
Get a scorecard
End the session and receive an honest, detailed rubric: what you nailed, what to fix, and a model answer for your deep-dive.
Get grilled, or get taught
Same voice, same whiteboard — you choose whether the AI assesses you or coaches you.
A rigorous mock
A skeptical staff engineer probes your design, pushes back on weak spots, and never hands you the answer. Ends with a judgmental scorecard so you know exactly where you stand.
- ✓Phased like a real 45-minute loop
- ✓Surfaces flaws with questions, not lectures
- ✓Hire / no-hire scorecard with scores
A guided lesson
A patient mentor teaches as you go — answering your questions, explaining tradeoffs, and building your intuition until the design is complete. Ends with an encouraging recap, not a verdict.
- ✓Ask anything, any time
- ✓Teaches the principle behind each decision
- ✓Recap of concepts + what to study next
Closer to the real interview than a peer mock
It sees your whiteboard
The interviewer reads your actual diagram every turn — you only get credit for what you draw, just like the real thing.
Phased like a real loop
Clarify, estimate, high-level design, deep-dive, scale & failure, wrap — it moves you through the arc a real interviewer follows.
Voice-native
You talk, it talks. No typing. That's the skill a system-design interview actually tests — thinking clearly out loud under questioning.
An honest scorecard
Every point is tied to something you said or drew, with a model answer for the component you went deepest on.
Learn mode too
Not interview-ready yet? Switch to a coaching session that teaches you the material instead of grading it.
Bring your own problem
Practicing for a specific company or domain? Paste your own prompt and the interviewer adapts to your track.
A scorecard you'd actually act on
Not vibes — a specific, senior-level read on how you did, tied to exactly what you said and drew.
Cheaper than one coffee per session
A live human mock runs $100 or more. Whitepad gives you unlimited access to a tireless senior interviewer for a fraction of that.
Start with one free mock — no card required.
Questions, answered
What kinds of interviews does it cover?+
System-design interviews across backend, iOS, and Android tracks today. You can also paste your own problem for a specific company or domain.
Do I need a microphone?+
Yes — it's a spoken interview, just like the real thing. Use headphones so your mic doesn't pick up the interviewer's voice.
How long is a session?+
About 45 minutes, phased like a real onsite. You can end early and still get a scorecard for what you covered.
Is it actually good feedback?+
The scorecard is generated by a top-tier model reasoning over your full transcript and final whiteboard, with every point tied to something concrete you said or drew.
Can I cancel anytime?+
Yes. Plans are month-to-month (or annual for a discount), and you can cancel from your account in one click.
Your interview is coming. Practice out loud.
Take your first mock free. Talk through a real system design problem, get an honest read, and walk in ready.
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