Difficulty changes what kind of questions you get, not how harshly you're marked.
The five modes
Warm up — easy openers to find your footing. Good for a first session or when you haven't interviewed in a while.
Recruiter screen — the first-call questions you'll really get. The default, and the right starting point for most people, because it's the round that actually filters.
Deep dive — probing follow-ups on the work itself. Use this when you know your first call will be with someone who does your job.
Leadership — influence, decisions, and tradeoffs. Not only for managers; senior individual contributors get asked these constantly.
Curveball — the unexpected ones, so nothing surprises you on the day.
How to use them
Start at Recruiter screen. If you're getting through comfortably, move to Deep dive, which is where most people find the gap between "I know this" and "I can explain this".
Do one Curveball session before a real interview. Not to master it — to have felt the sensation of being asked something you didn't prepare for, so it isn't new.
Switch modes mid-session from the compact dropdown if the level is wrong.
The Interviewer Lens
Optional, per question. It shows you what's going on behind the question in three parts:
Signal — what they're actually trying to find out. Often not what the question literally asks. "Tell me about a conflict with a colleague" is rarely about the conflict.
Trap — the common way people damage themselves answering it. Blaming the colleague, in that example.
Move — the approach that works. What to lead with, what to leave out.
When to open it
Before answering when you're learning a question type and want to understand it. After answering when you want to test yourself first and then see what you missed — which is the more useful order once you're past the basics.
It's off by default. A lens on every question turns rehearsal into reading.
Good to know
- Difficulty doesn't change the coaching. It changes the questions.
- Questions still come from your own resume in every mode — a Curveball question is an unexpected question about your experience, not a brain-teaser.
- Anything worth keeping from a session lands on your Interview Card.