Real Questions

Real Questions Asked Recently (2024–2025)

• Google (L7 Frontend): “Design YouTube’s recommendation grid with infinite scroll and prefetching.”
• Meta (E6): “How would you rebuild Instagram Stories with 60fps swipe on $100 Android phones?”
• Stripe (Staff): “Design the new Stripe Dashboard with 300+ pages and 100ms navigation.”
• Netflix (Senior Staff): “How do you A/B test UI changes for 250M users with zero regression?”
• Robinhood (Principal): “Design a candlestick chart that updates 1000 times/second without jank.”

Bonus Deep Technical Questions

• Explain the difference between useLayoutEffect and useEffect at the browser paint level.
• How does React Forget (upcoming compiler) change how we write React?
• Explain V8 Sparkplug compiler and how it affects startup time.
• How do you implement a virtual DOM diffing algorithm from scratch?

Q48. Google (L7 Frontend): “Design YouTube’s recommendation grid with infinite scroll and prefetching.”

Q49. Meta (E6): “How would you rebuild Instagram Stories with 60fps swipe on $100 Android phones?”

Q50. Stripe (Staff): “Design the new Stripe Dashboard with 300+ pages and 100ms navigation.”

Q51. Netflix (Senior Staff): “How do you A/B test UI changes for 250M users with zero regression?”

Q52. Robinhood (Principal): “Design a candlestick chart that updates 1000 times/second without jank.”

Q53. Explain the difference between useLayoutEffect and useEffect at the browser paint level.

Q54. How does React Forget (upcoming compiler) change how we write React?

Q55. Explain V8 Sparkplug compiler and how it affects startup time.

Q56. How do you implement a virtual DOM diffing algorithm from scratch?