How it works
A method you can inspect, not a black box that scores you
Interview practice only helps if you know what's being measured and why. Here is exactly how a session runs and how the feedback is produced.
1. Setup takes under a minute
Choose a playground, confirm whether you're speaking or typing, and check your microphone if you're speaking. Nothing records until you press record.
2. The interview runs on a clock
The interviewer reads each question aloud with captions on screen. You can replay a question or ask for clarification, exactly as you would with a human panel. Each question has a suggested answer length so you learn the shape of a good response.
3. Your answers are assessed against expected signals
Every question is written with a list of the signals it's designed to surface — a trade-off named, a failure mode acknowledged, a metric quoted. Your answer is compared against those signals rather than against a model answer.
4. Feedback arrives immediately
Six competency scores, the two things you did well, the two things to fix first, and an answer-by-answer breakdown with a stronger example for each.
5. You repeat with the weak spot in view
The report recommends the next playground based on where you lost the most ground, so the second session isn't just the first one again.
The six competencies
Every session scores the same six dimensions so you can compare across roles and formats. The weighting shifts by playground — a system design session leans on trade-offs, a screening session leans on communication.
- Technical accuracy
- Correctness and depth: are the mechanisms you describe accurate, and do you know where the edges are?
- Reasoning
- How you get to an answer: assumptions stated, constraints identified, conclusions that follow from the evidence.
- Communication
- Whether a busy panel can follow you: pacing, plain language, and answering the question that was asked.
- Structure
- Headline first, then support, then close. The single most common gap in otherwise strong answers.
- Trade-off awareness
- Naming what an option costs, not just what it buys. Senior interviews are largely won here.
- Role fit
- Whether your examples and priorities match the level and remit you're interviewing for.
What the readiness score is — and isn't
It is a directional practice signal calculated only from the answers you gave in a single session. It tells you whether your answers are getting more complete, better-structured and more specific over time.
It is not a prediction of whether you'll pass a real interview, not a benchmark against other candidates, and not a measure of your ability as an engineer. No employer sees it and it is never shared.
Treat a rising trend as evidence your preparation is working, and a specific low competency as the thing to practise next. Ignore the absolute number.