System design prep built for staff+ engineers
ChatGPT gives you answers. We find your blind spots.
Calibrate yourself in 5-minutes. No prep needed. No pressure.
Calibrate for freeGeneric prep breaks at staff level.
EVERY OTHER PLATFORM
- "Design a URL shortener" for the 50th time
- Same questions for L3 and L6
- Surface-level feedback
- No pressure, no follow-ups
PAI STAFF PRACTICE
- When to push back on requirements and reframe the problem
- How to articulate why you chose eventual consistency over strong — and when you'd change your mind
- Driving the interview instead of responding to it
- Drills calibrated to staff expectations
Staff-level drills, not tutorials.
5-minute focused challenges. Do one between meetings.
User clicked "Buy" twice
Network retries, browser refreshes, multi-tab submissions. Design the locking strategy that prevents double charges.
500M WebSocket connections
Partition half a billion connections evenly. What breaks at this scale?
AZ fails, reconnect everything
Design retry and reconnection without thundering herd.
50K RPS on single Postgres
Team wants Redis in front. Argue for or against.
Why Candidates Trust PAI
To Ace Problem Solving In Interviews
Practice Targeted Drills under pressure
Just in Time hints to unblock you
Get structured, actionable feedback at every step
What Our Users Love About PAI
Pricing
FAQ
Mid-to-senior engineers (SDE2+) prepping for high-stakes interviews at top tech companies. If you want your problem solving depth tested under real pressure — this is for you.
Each session mirrors the stakes, ambiguity, and time constraints of senior-level system design rounds — open-ended, evolving, no canned answers
With the rise of AI tools, the barrier to entry for writing code has dropped. This makes Problem Solving—the ability to debug, scale, and architect correctly—the primary differentiator for top-tier engineering roles. We help you practice the high-level judgment skills that AI can't fake.
Most problem solving drills take 10-15 minutes for senior engineers. But there’s no fixed clock: go as deep as you want, pause anytime, and pick up right where you left off
No scheduling, no waitlists. Log in anytime, pick a scenario, and run your interview on your terms.
Always. Your sessions and feedback stay in your dashboard so you can resume them anytime and review how your depth improves.
It’s all free! For a limited time. Practice as much as you want.
A live mock interview with a senior engineer can cost anywhere between $300–$600 an hour — and the quality isn’t always guaranteed! PAI gives you repeatable, high-fidelity sessions for a fraction of that so you build depth, without any bias, on demand, as many times as you want.