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Software Engineer interview questions (2026)
Software Engineer interviews in the UK are assessed on coding & code quality, system design, collaboration & code review, usually across 4 stages — phone or video screen, then competency and behavioural questions, then panel interview, then technical interview or test. The 12 questions below are the ones actually asked, each with what a strong answer does.
Researched, current questions asked in real software engineer interviews in the UK (Technology & IT), with what a strong answer actually does. Questions marked 2026 are the newer, AI-era questions employers now ask. Last reviewed 2026-07-22.
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What they assess
- Coding & code quality
- System design
- Collaboration & code review
- Delivery & ownership
- AI-assisted development
How a software engineer interview usually runs
- Phone or video screen
- Competency and behavioural questions
- Panel interview
- Technical interview or test
The questions to expect
Tell me about the most complex bug you've tracked down. How did you find it?
Narrate the hunt: reproduce, isolate, hypothesise, prove. The methodical process is what's being scored, not the bug's exotic-ness.
Tell me about a code review where you and the author disagreed. How was it resolved?
Code-review judgement is weighed more heavily now. Show you argued from impact, knew which battles mattered, and kept the relationship.
Describe a time you shipped late or had to cut scope. What did you tell stakeholders, and when?
Early, honest communication is the win condition. Show the trade-off you proposed rather than the apology you made.
Tell me about a design decision you made that had to scale later. What happened?
Show you designed for known load, not imagined load — and how you evolved it when reality arrived. Honest hindsight scores well.
Design a URL shortener (or similar small service): data model, API, and how it scales.
Clarify requirements first, state your assumptions out loud, and name trade-offs as you go. Structure beats a perfect final diagram.
How would you add tests to a codebase that has none?
Start where the risk is: pin down current behaviour with characterisation tests, cover the money paths, then ratchet coverage in CI.
What happens between typing a URL into a browser and the page appearing?
A depth-check classic. Give the backbone (DNS, TCP/TLS, request, render) then go deep where your role lives — don't recite all layers equally.
Why software engineering — what keeps you in it?
A specific true thing — the itch of debugging, shipping to real users — lands better than 'I love problem solving'.
If you could use an AI assistant in this coding interview, how would you use it — and how would you check its output?2026
Show a loop: precise prompt, read every line, test the edges, refactor to your standard. Delegating typing is fine; delegating judgement isn't.
How has AI changed the way you write and review code day to day?2026
Name real tools and one workflow that changed — plus a time the tool was confidently wrong and how you caught it.
Tell me about a time you explained a technical problem to someone non-technical.
Pick a real audience and show the translation: the analogy you used, what you left out, and how you checked they got it.
Describe a production incident you were involved in. What did you do first?
Order matters: mitigate, communicate, then root-cause. Finish with the fix that stopped it happening again.
How to prepare for a software engineer interview in the UK
UK loops typically run phone screen → technical (pairing or take-home) → behavioural/panel. Ask whether AI assistants are allowed in the coding round — policies now differ by employer and asking shows judgement.
How Technology & IT interviews are run in 2026
- Coding rounds increasingly allow — or expect — an AI assistant: you are marked on how you prompt, verify and fix its output, not typing speed. Live reasoning, debugging and code-review rounds have grown to compensate.
- System design and 'explain your thinking out loud' rounds carry more weight than puzzle-style coding; many employers explicitly verify real-time reasoning because take-homes are now AI-solvable.
- Volume employers screen with async one-way video and online tests before any human round, so camera practice matters at the top of the funnel.
Turn this into a plan
A list of questions is a start; a programme is what changes the outcome. Intervooh builds a day-by-day plan for your exact software engineer interview — company research, story building with an AI coach, spoken practice with delivery feedback, and scored mock interviews. It never writes your answers for you.
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