These are HLD questions of the kind TCS actually asks — the patterns that keep coming back in TCS's AI project interviews, where what matters is applying HLD sensibly for clients rather than research depth. Treat this page as a mock interview: say every answer out loud before revealing it. If one surprises you, the lesson behind it is linked at the bottom.
TCS HLD concept questions
A TCS system design round asks: what are the first three things you should clarify before designing any system, given only a one-line prompt like 'design a notification system'?
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A TCS interviewer asks you to explain, in simple terms, why adding a cache in front of a database helps performance, and what the main risk is.
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TCS HLD applied & hands-on questions
TCS-style: a web application runs on 4 identical app servers behind a load balancer. Which routing algorithm — round robin or least-connections — would you pick if some requests take much longer than others (e.g. a report-generation endpoint), and why?
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How to use this page: TCS rarely asks something you've never seen — they ask a standard HLD concept and then push one level deeper ("why?", "what would you do if..."). Master the concept in the HLD course lessons, and the follow-up stops being scary.
Keep practising: Caching Explained, Databases at Scale, Design a URL Shortener and Interview Framework cover what most TCS HLD rounds test — and the TCS NQT exam guide covers the rest of their selection process.