Service vs product companies: two entirely different interview tracks

If you're prepping for both IT services and product companies with one strategy, you're prepping wrong. The interview shapes are different enough that you need separate study plans.

Service company process — TCS, Infosys, Wipro, Cognizant, Accenture, Capgemini. The funnel is wide and standardised. Aptitude test (quant, logical, verbal) is round one and the biggest filter. Round two is usually a 30-minute technical chat covering OOP basics, one language deep (Java or Python), SQL fundamentals, and a couple of project questions. Round three is HR — communication, willingness to relocate, salary expectations. Coding tests, when present, are LeetCode Easy-to-Easy-Medium.

Product company process — Flipkart, PhonePe, Razorpay, Swiggy, Zomato, Atlassian, Postman. FAANG-style. Online assessment with 2–3 LeetCode Medium / Hard problems. Then 3–5 rounds: DSA round (graphs, DP, sliding window), low-level design (e.g., parking lot, BookMyShow), high-level system design (chat app, URL shortener), behavioural / culture fit, and often a hiring manager round.

What to actually do. For services: heavy aptitude practice, polish one language deep, prep STAR-format project narratives. For product: 200+ LeetCode mediums, two design rounds practiced with someone, a written portfolio of 2–3 systems you've actually shipped.

At mid-senior levels (5+ years), product companies care less about LeetCode brilliance and more about your last architectural decision and what you measured. Have a 10-minute story about one system you owned, what trade-offs you made, and what you'd do differently.