PayU Interview Experience

Technical Round

Predict the output of this code: console.log(1); setTimeout(() => console.log(2), 0); Promise.resolve().then(() => console.log(3)); console.log(4); Explain the event loop mechanism that determines …

Implement Promise.allSettled from scratch without using the native method. Then explain the difference between Promise.all, Promise.allSettled, Promise.any, and Promise.race — give a concrete payment…

Explain the reconciliation algorithm in React. How does React decide which DOM nodes to update when state changes? What is the role of the key prop and what happens when you use an array index as a k…

System Design Round

You are building a multi-step payment flow: Cart → Address → Payment Method → OTP → Confirmation. Each step has its own data, validation, and API calls. How would you architect state management for t…

Design the frontend architecture for a PayU checkout SDK that can be embedded in any merchant website as a script tag. It must render a payment form in an iframe, handle cross-origin communication, s…

PayU wants to run A/B tests on the checkout button colour and payment method ordering to improve conversion rates. As the frontend engineer, how would you design the experimentation infrastructure: f…