How practice quiz levels work
Three difficulty tiers, one shared pool per subject, one 30-minute clock. Pick the tier that matches where you are - or take all three back-to-back.
Who it's for: First OA of the season, or first time on this topic.
How it feels: Confidence build. Easy-heavy mix, generous time budget per question.
Who it's for: You've cleared a few OAs and want realistic calibration.
How it feels: Medium-weighted. Same pacing you'd see on a mid-tier product-based company OA.
Who it's for: Prepping for MAANG-tier or a late-stage round.
How it feels: Hard-heavy. Same 30-minute clock - tighter per-question budget by design.
The pool per subject
Every subject has a practice pool - a set of questions authored and tagged by difficulty. The target is 100 per subject (roughly 40 easy · 30 medium · 30 hard). Some subjects are still growing; when the pool is smaller than what a level asks for, you'll simply get fewer questions - no reshuffling of difficulty tags to fake a full quiz.
Every attempt samples fresh questions at random. Two back-to-back attempts on the same level will rarely be identical, and never repeat within one attempt.
The 30-minute timer
Flat across all three levels for now - 30 minutes wall-clock, server-side. The badge on the quiz page counts down and turns amber at 15 minutes left, then red at 5 minutes left. At zero, whatever you've answered is submitted automatically - partial credit beats a lost attempt.
Expert covers 30 questions in the same 30 minutes, which is about 60 seconds per question - tight but survivable because the mix leans on pattern recognition, not long trace-throughs.
Scoring & retakes
Every quiz is scored on the server against the sampled set for that attempt. Your history at /assessments/attempts slices by subject × level, so Backend · fresher #3 and Backend · expert #1 are separate counters. Retakes are unlimited and always sample fresh - treat it like a batting net, not a one-shot exam.
Free forever
Every level is free in this phase. If we ever gate longer drills behind a subscription, the three canonical levels above stay free. Anything paywalled will be a clearly-marked add-on, not the core loop.