Software Engineer interview questions & mock practice
A Software Engineer interview in 2026 runs across 4 rounds — online assessment, dsa / problem solving, system design, hiring manager / culture fit. Below are the most-asked Software Engineer interview questions and a focused prep plan. Rehearse every answer with OnJob's free AI mock interview and get instant, specific feedback before the real one.
The Software Engineer interview process
Coding, data structures, algorithms and system design — the core software engineering loop used by product companies and startups across India.
Online assessment
Timed coding problems on arrays, strings and hashing on HackerRank or HackerEarth.
DSA / problem solving
1–2 live coding rounds on data structures, algorithms and complexity analysis.
System design
Designing a scalable service (mid/senior); low-level design for early-career.
Hiring manager / culture fit
Past projects, ownership, behavioural questions and team fit.
Most-asked Software Engineer interview questions
12 of the questions Software Engineer candidates are asked most often in India. Practise answering each one out loud in your AI mock interview.
- 1. Reverse a linked list, both iteratively and recursively.
- 2. Find the two numbers in an array that add up to a target sum.
- 3. Detect whether a linked list has a cycle.
- 4. What is the difference between a process and a thread?
- 5. Explain time and space complexity (Big O) with examples.
- 6. How does a hash map work internally, and what happens on collisions?
- 7. Find the longest substring without repeating characters.
- 8. What is the difference between an array and a linked list?
- 9. Explain the difference between SQL and NoSQL databases.
- 10. How would you design a URL shortener like bit.ly?
- 11. What happens when you type a URL into a browser and press enter?
- 12. Tell me about a challenging bug you fixed and how you approached it.
How to prepare for your Software Engineer interview
Drill 150–200 DSA problems on arrays, strings, hashing, trees and graphs — pattern recognition beats memorising solutions.
Always state your approach and complexity out loud before you start coding; interviewers grade communication, not just the answer.
Revise core CS fundamentals: OS (processes, threads, deadlocks), DBMS (indexing, normalisation, transactions) and networking basics.
Practice system design from first principles: load balancing, caching, sharding, and the CAP theorem.
Prepare 3–4 STAR stories about real projects you can speak to in depth for the behavioural round.
Practise other roles
- Frontend Developer
- Backend Developer
- Full Stack Developer
- Data Analyst
- Data Scientist
- Product Manager
- DevOps Engineer
- Java Developer
- Python Developer
- UI/UX Designer
- Sales / Business Development
- Digital Marketing
- HR / Recruiter
- Accountant
- Customer Support
- Data Engineer
- Machine Learning Engineer
- QA / Test Engineer
- Android Developer
- iOS Developer
- Business Analyst
- Project Manager
- Scrum Master
- SQL Developer
- React Developer
- Node.js Developer
- Cloud Engineer (AWS)
- Cybersecurity Analyst
- Network Engineer
- Database Administrator
- SEO Specialist
- Content Writer
- Graphic Designer
- Sales Executive
- Business Development Manager
- Operations Manager
- Financial Analyst
- Chartered Accountant
- Customer Success Manager
- Technical Support Engineer
- Civil Engineer
Software Engineer interview — FAQs
What questions are asked in a Software Engineer interview?
Common Software Engineer interview questions include: Reverse a linked list, both iteratively and recursively. Find the two numbers in an array that add up to a target sum. Detect whether a linked list has a cycle. What is the difference between a process and a thread? Interviews usually run across 4 rounds — Online assessment, DSA / problem solving, System design, Hiring manager / culture fit. Practice all of them with instant AI feedback using OnJob's free mock interview.
How many rounds are in a Software Engineer interview?
A typical Software Engineer interview has 4 rounds: Online assessment (Timed coding problems on arrays, strings and hashing on HackerRank or HackerEarth.); DSA / problem solving (1–2 live coding rounds on data structures, algorithms and complexity analysis.); System design (Designing a scalable service (mid/senior); low-level design for early-career.); Hiring manager / culture fit (Past projects, ownership, behavioural questions and team fit.).
How do I prepare for a Software Engineer interview?
To prepare for a Software Engineer interview: Drill 150–200 DSA problems on arrays, strings, hashing, trees and graphs — pattern recognition beats memorising solutions. Always state your approach and complexity out loud before you start coding; interviewers grade communication, not just the answer. Revise core CS fundamentals: OS (processes, threads, deadlocks), DBMS (indexing, normalisation, transactions) and networking basics. Then run a full AI mock interview on OnJob to rehearse out loud and get instant, specific feedback before the real thing.
What skills do I need for a Software Engineer role?
Core Software Engineer skills tested in interviews include Data Structures, Algorithms, System Design, OOP, SQL, Git, Problem Solving. OnJob shows you exactly which of these skills stand between you and a 100% match on every live Software Engineer job.
Is OnJob's Software Engineer mock interview free?
Yes. OnJob's AI mock interview is free to start (₹0) and gives you instant feedback on your answers. Pro (₹99/month) adds unlimited interview-prep AI alongside recruiter tracking and unlimited applications.
Ace your Software Engineer interview
Rehearse every Software Engineer question out loud with OnJob's AI mock interview and get instant, specific feedback. Then apply to AI-matched jobs in one click — free to start.
Everything about Software Engineer on OnJob
Move across the whole Software Engineer topic — live openings, real salary data, the job description, interview prep, and early-career routes — all in one place.