Answer realistic questions, get rubric-based feedback, and turn each weak spot into your next focused drill.
Question
Overall score
3.2 / 5
Needs improvementTop feedback
Missing performance metrics
No bottleneck classification
No verification step
Better answer preview
I'd start by capturing a performance profile in React DevTools to identify wasted renders...
View full feedbackHow it works
Each session stays focused, then turns your feedback into a clear next step.
Choose a standard mock, a quick drill, or a deep coaching pass. The setup keeps the interview scoped to the topics you need.
Quick drill
Targeted practice
Standard mock
5 questions · 25 min
Deep coaching
Targeted practice
Answer one question at a time with progress, guide rails, hints, and space to write a structured response.
Question 1 of 5
Explain how React reconciliation uses keys during list updates.
Every answer produces dimension scores, missed points, a better answer, and recommended next sessions.
Correctness
4 / 5
Depth
3 / 5
Communication
3 / 5
Optional CV personalization
Add your CV anytime and the coach can turn your projects, roles, and technical background into more relevant interview questions.
Get questions about real projects and decisions.
Prepare for follow-ups that probe depth and trade-offs.
Remove your CV anytime. It is optional for every session.
Your experience becomes interview context.
Frontend Engineer
Fintech platform
Built verification workflows and internal review tools.
Software Engineer
Consumer product
Improved frontend performance across high-traffic flows.
Personalized question ideas
How would you measure the impact of the workflow you shipped?
Which performance trade-offs did you make under real traffic?
Personalized dashboard
Turn interview feedback into a technical practice plan. See the gaps, then launch the drill that targets them.
Track whether your answers improve across sessions.
Compare React, browser APIs, testing, and performance.
See the exact concepts missing from recent answers.
Practice the follow-up most likely to expose the gap.
Dashboard · performance review
Specific gaps from recent answers
React rendering
2.1/5
Did not separate wasted renders from long tasks or layout thrash.
Web Performance
2.4/5
Skipped INP measurement, Lighthouse CI budgets, and regression gates.
Browser APIs
2.8/5
No IntersectionObserver threshold or requestIdleCallback trade-off.
Built from your latest feedback
Next technical drill
Use React Profiler and INP traces to isolate render work, handler cost, and layout thrash before choosing a fix.
Queue next
Lighthouse CI performance budgets
IntersectionObserver pagination edge cases
See the difference
Every answer gets scored, gap-analysed, and rewritten at senior level so you know exactly what to improve.
"React updates the DOM when state changes. It compares the old and new virtual DOM and only updates what changed. This makes it faster than updating the whole page."
"React's reconciler uses a fiber architecture for incremental work. It diffs a work-in-progress tree against the current tree — elements of different types unmount/remount, same types update in place. Keys give stable identity across re-renders, avoiding O(n³) list comparison. In concurrent mode, this work is interruptible via lanes..."
Coverage
Pick what you want to drill. Mix topics. Filter by difficulty.
Pricing
No credit card to get started. Upgrade only if you want unlimited sessions and the full study system.
Free
Good for trying it out.
Pro
Or $19 one-time — pay once, prep forever.
No subscription traps. Cancel or keep free tier anytime.
FAQ
Frontend engineers preparing for junior through staff-level interviews, with a strong focus on senior-level depth.
JavaScript, React, browser APIs, web performance, frontend system design, testing, and behavioral communication.
You receive rubric-based scores, missing points, a stronger answer example, and recommendations for your next session.
Yes. You can start with a free session and decide whether the deeper practice workflow is useful for your preparation.
Practice with a clear next step
Three questions. Honest AI feedback. Five minutes well spent.
No credit card required · No CV required · Add one anytime for personalized questions
