Dev Software Engineer Interview: Questions & Prep (2026)

Dev currently has 70 open Software Engineer roles (knok jobradar, July 2026). Across all of India right now, there are 4,998 Software Engineer openings, so standing out in the interview process matters more than ever. Candidates at Dev typically go through multiple rounds covering coding, system design, and behavioural questions. The exact format varies by team and seniority level, so confirm the structure with your recruiter before you start preparing. Salary bands for Software Engineers in India (2026)

Use these ranges as a starting point. For more granular benchmarks, Glassdoor and levels.fyi are publicly reported sources worth checking before the offer stage.

Based on candidate reports and the nature of software engineering work, here are the questions that come up most often at Dev: 1. Walk us through a complex technical problem you solved end-to-end. What was the challenge, your approach, and the outcome?
2. How would you design a system that needs to scale quickly? For example: 'Design a real-time notification service for a high-volume product.'
3. Describe a time you disagreed with a technical decision. How did you raise it, and what happened?
4. How do you approach code reviews? What do you look for, and how do you give feedback that lands well?
5. What are the trade-offs between microservices and a monolithic architecture? When would you choose one over the other?
6. How do you handle technical debt in a production codebase? Give a specific example if you can.
7. Describe your debugging process when you hit an unfamiliar production issue.
8. Tell us about the project you are most proud of. What was your specific contribution, and why does it matter?
9. How do you ensure your code stays testable and maintainable as the system grows?
10. Tell us about a time you had to learn a new technology under time pressure. How did you ramp up and still deliver?
11. How do you collaborate with product managers or designers when requirements are unclear?
12. Where do you see the software engineering field heading in 2026-2027, and how are you keeping up?

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Answer 1 Q: Walk us through a complex technical problem you solved end-to-end. *Situation:* 'Our team's nightly batch pipeline was taking several hours to complete, causing the morning dashboards to refresh late, which business teams relied on for their first standup of the day.' *Task:* 'I was assigned to investigate the bottleneck and bring the processing window down to something the business could actually work with.' *Action:* 'I profiled the pipeline stage by stage and found the biggest slowdown was sequential database writes that could be batched. I rewrote the critical path to use bulk inserts, added an index that was missing on a frequently joined column, and moved a CPU-heavy transformation step to a background worker pool. I also added structured logging so the next engineer could debug it without starting from scratch.' *Result:* 'The pipeline run time dropped significantly, the dashboards now refresh before standup, which was the outcome the business team actually cared about. The structured logging caught a separate data issue some weeks later, so the investment paid off twice.' ---

Answer 2 Q: Describe a time you disagreed with a technical decision. *Situation:* 'My tech lead proposed migrating a stable internal service to a new framework right before a major product release, calling it a 'modern best practice.'' *Task:* 'I needed to raise my concerns constructively without coming across as resistant to change, and ideally influence the plan before any work started.' *Action:* 'I prepared a short written document comparing migration effort, risk, and benefits side by side. I proposed a phased approach: spike the new framework on a low-risk internal tool first, gather learnings, then migrate the critical service after the release. I shared the document in our team channel before the meeting so people could read it in advance rather than reacting in the moment.' *Result:* 'The team agreed to the phased plan. The spike revealed a compatibility issue we had not anticipated, which would have been painful to hit mid-migration on a critical service. My tech lead later said that writing it down had made the discussion far more productive than it would have been otherwise.' ---

Answer 3 Q: Tell us about a time you had to learn a new technology under time pressure. *Situation:* 'Our team was asked to integrate with a third-party payments API that none of us had used before. The integration had a hard go-live date tied to a signed business contract.' *Task:* 'I volunteered to own the integration. I had a tight sprint deadline to learn the API, build the integration layer, and write tests, all at once.' *Action:* 'I read the official documentation end-to-end on the first day and built a minimal working prototype immediately after. I joined the provider's developer forum and found answers to two edge cases I was stuck on. I built incrementally, happy path first, then error handling and retries. As I went, I wrote a short internal wiki page so the knowledge would not live only in my head.' *Result:* 'We shipped on time with no critical bugs in QA. The wiki page became the team's go-to reference when the integration needed to be extended some months later.'

STAR, the backbone of every behavioural answer

Keep each STAR answer to 2-3 minutes when spoken aloud. Trim Situation and Task, interviewers want to hear the Action. ---

For system design rounds: structure before you sketch 1 Clarify requirements first, read/write patterns, scale expectations, latency needs
2. Identify core entities, what are the main data models?
3. Sketch the high-level architecture, clients, API layer, services, databases, queues
4. Deep-dive on one component the interviewer signals interest in
5. State trade-offs explicitly, close with what you would change given more time or different constraints ---

For coding rounds: think before you type State your approach out loud before writing a single line of code. Ask about edge cases upfront. Interviewers evaluate your reasoning process, not just whether the code compiles.

Regardless of the specific questions asked, Dev interviewers typically look for these signals: 1. Clear thinking under uncertainty
Can you break an ambiguous problem into structured steps? Do you ask the right questions before jumping to a solution, or do you assume and dive in? 2. Individual ownership
Interviewers want to hear 'I', not 'we'. What was your specific contribution? Did you see the problem through to the end, or hand it off at the first obstacle? 3. Trade-off awareness
There is rarely one right answer in engineering. Candidates who articulate what they would sacrifice for a given design choice, and why, come across as more experienced than those who present a single solution as the obvious right one. 4. Communication across roles
Can you explain a technical decision to a product manager or business stakeholder without losing the key point? This skill shows up in behavioural questions and is weighted more heavily at mid and senior levels. 5. Genuine curiosity and continuous learning
The 2026 engineering landscape shifts fast. Interviewers respond well to candidates who name something concrete they have learned recently and applied at work, not just bookmarked or read about.

A structured preparation plan Phase 1, Coding fundamentals****
- Revise data structures and algorithms: arrays, hashmaps, trees, graphs, dynamic programming
- Solve at least one coding problem per day in the language you plan to use in the interview
- Review time and space complexity (Big-O), be ready to discuss it out loud during the round Phase 2, System design
- Study common building blocks: load balancers, caches, databases, message queues, CDNs
- Practice designing systems out loud, record yourself if you can, then replay and critique
- Read real-world architecture write-ups from engineering blogs to build vocabulary Phase 3, Behavioural prep
- Write out several STAR stories from your career covering: conflict, failure, fast learning, cross-functional collaboration, and a moment of ownership or leadership
- Practice each story aloud, aim for 2-3 minutes per answer
- Be ready to go deeper on any story the interviewer probes Phase 4, Mock interviews and company research
- Do at least one full mock interview with a peer or mentor before the real thing
- Research Dev's products, engineering culture, and any publicly available technical content
- Prepare 3-4 smart questions to ask your interviewer about team structure, engineering challenges, and how success is measured in the role On the day
- Re-read the job description before you start
- Think and speak aloud from the first minute of any coding or design round
- Close every round with your prepared questions, it signals genuine interest If you are actively applying while you prepare, knok checks 150+ job sites nightly, applies to roles that match your resume, and messages HR on your behalf, so your search keeps moving even while you are heads-down studying.

1. Starting to code before clarifying the problem
The single most common mistake in coding rounds. Spend a few minutes asking questions and stating your assumptions before writing anything. 2. Saying 'we' throughout behavioural answers
Interviewers are assessing you as an individual. If every story describes what 'the team' did, you have not told them anything specific about your own contribution or judgement. 3. Presenting system design as a single 'right' answer
Candidates who do not acknowledge trade-offs or weaknesses in their design come across as less experienced than those who openly discuss constraints and what they would do differently. 4. Neglecting the behavioural round
Many mid and senior-level candidates lose offers not because of weak coding but because of vague, unstructured answers to questions like 'tell me about a conflict.' STAR practice is not optional at any level. 5. Asking no questions at the end
Saying 'I have no questions' reads as low interest in the role. Prepare at least a couple of thoughtful questions about the engineering challenges, team dynamics, or how performance is measured. 6. Overselling your individual contribution
Be specific and honest about what you personally built or decided. If you built one module of a large system, say so, do not claim you 'architected the whole platform.' Interviewers probe, and vague claims fall apart quickly.