Software Engineer Interview Questions
India 2025

💡 How to answer: Processes are independent memory spaces; threads share memory within a process. Threads are lighter but need synchronisation. Mention use cases for each.

💡 How to answer: Big-O notation measures how runtime grows with input size. O(1) is constant, O(n) is linear, O(n²) is quadratic. Always relate to real code — nested loops = O(n²).

💡 How to answer: Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, Dependency Inversion. Give a concrete code example for at least one.

💡 How to answer: SQL: relational, ACID, fixed schema — good for transactions. NoSQL: flexible schema, scales horizontally — good for high-volume, unstructured data. Mention when to use each.

💡 How to answer: JVM uses generational GC — Young/Old/Perm Gen. Python uses reference counting + cyclic GC. Explain memory leaks and how to avoid them.

💡 How to answer: Stateless, client-server, uniform interface, cacheable. REST constraints — HTTP verbs (GET/POST/PUT/DELETE), status codes, JSON payload. Contrast with SOAP.

💡 How to answer: Clarify requirements → estimate scale → define APIs → choose DB → design components → handle edge cases. Show scalability thinking.

💡 How to answer: Containerisation tool. Packages app with dependencies into isolated containers. Benefits: consistent environments, fast deploys, microservices isolation.

💡 How to answer: Check execution plan (EXPLAIN), add indexes, avoid SELECT *, use JOINs efficiently, consider caching with Redis, denormalise where needed.

💡 How to answer: Consistency, Availability, Partition tolerance — you can only guarantee 2 of 3. Cassandra favours AP; HBase favours CP. Real-world implications for distributed systems.

💡 How to answer: Structure: Current role → 2–3 key technical achievements → core tech stack → why this role. Keep to 90 seconds. Lead with your strongest skill.

💡 How to answer: Use STAR. Show you raised concerns with data/evidence, were open to the team's reasoning, and could disagree and commit when needed.

💡 How to answer: Own the failure, show root cause analysis, demonstrate specific changes you made afterward. Growth mindset is what interviewers want to see.

💡 How to answer: Prioritise ruthlessly, communicate early about risks, cut scope not quality, ask for help. Give a specific example where you delivered under pressure.

💡 How to answer: Senior engineer / tech lead / architect. Tie your growth to the company's technical challenges. Show ambition with self-awareness.

💡 How to answer: Immediately alert stakeholders, stop the bleeding (rollback/feature flag), preserve logs, identify root cause, fix with tests, post-mortem documentation.

💡 How to answer: Ask clarifying questions, break into known vs unknown, give a range estimate, identify risks early, propose a spike/prototype for unknowns.

💡 How to answer: Triage by severity, fix P0 blockers, document P1/P2 as tracked debt, communicate to PM, do not release silently with known critical issues.

💡 How to answer: Never give first. Say: 'I'd like to understand the full role and responsibilities before discussing numbers. What is the budgeted range for this position?'

💡 How to answer: Quantify your value: skills gap you fill, ramp-up cost saved, market rate data (cite Naukri salary insights). Negotiate on joining bonus or ESOPs if base is fixed.

💡 How to answer: Shows architectural curiosity. Great question to understand tech debt and modernisation roadmap.

💡 How to answer: Shows you want to contribute, not just collect a salary. Listen carefully — the answer tells you about team health.

💡 How to answer: Critical for work-life balance. Shows operational maturity awareness.