Razorpay, Swiggy, PhonePe, and Zerodha all weight system design 40-50% of senior interviews. Here is the exact framework that gets offers — and the trap questions that filter out 80% of candidates.

System design interviews at top Indian product companies follow a predictable pattern but most candidates fail by jumping to solutions before clarifying requirements. The framework that works: spend 5 minutes on functional + non-functional requirements, 5 on capacity estimation, 10 on high-level design, 15 on deep dives. The trap questions: "design WhatsApp" usually wants you to focus on message ordering and offline delivery, not the chat UI. "Design Razorpay checkout" wants idempotency, retry logic, and webhook reliability — not the payment form. Always ask "what scale" before designing — a 1M DAU product needs different choices than a 100K DAU one. Prep resource that actually helps: Alex Xu's System Design Interview Vol 1 + 2. Skip YouTube influencer videos — they're shallow. Practice 30 problems out loud with HelloInterview or with a friend.