Graduate Software Engineer Interview Questions UK: 8 Real Questions and What Interviewers Want

Before your Graduate Software Engineer interview, it helps to see the questions from the interviewer's side. We have picked eight from our set of 25 and added the reason each one gets asked.

Eight Graduate Software Engineer interview questions, and what the interviewer is thinking

1. Why do you want to be a software engineer, and why this graduate scheme rather than another route in?

Why they ask: They want to see genuine motivation for engineering and an understanding of what a graduate programme offers.

2. Can you explain the four pillars of object-oriented programming with examples from code you've written?

Why they ask: This is a staple graduate question testing whether you can apply theory rather than recite definitions.

3. What is the difference between an array and a linked list, and when would you choose each?

Why they ask: Data structure fundamentals are tested in almost every graduate interview and online assessment.

4. Explain Big O notation and tell me the complexity of binary search and why.

Why they ask: They want to confirm you can reason about algorithm efficiency, a core graduate skill.

5. Tell me how you use Git, including branching, pull requests and how you'd resolve a merge conflict.

Why they ask: Version control is essential from day one in a team, and graduates often have limited team experience of it.

6. What makes a good unit test, and how would you test a function that calculates a discount?

Why they ask: Testing discipline is something graduate employers want to see early, and the discount example checks practical thinking.

7. You've been stuck on a bug for most of the day. What do you do?

Why they ask: Graduates who struggle silently can waste days, so they want to see sensible help-seeking and structured debugging.

8. Tell me about a technical project you built at university or in your own time that you're proud of.

Why they ask: Graduates have limited work history, so projects show initiative, technical ability and how you work.

A sample answer to question 1

Why do you want to be a software engineer, and why this graduate scheme rather than another route in?

I've enjoyed building things since my first year at university, when I wrote a small timetable app for my course group and watched people actually use it. That moment of solving a real problem with code is what I want to do every day. I'm choosing a graduate scheme specifically because I want structured learning alongside real delivery. My degree gave me strong fundamentals in data structures, algorithms and object-oriented design, but I know professional engineering is different: code review, working in a team on a shared codebase, testing properly, deploying and supporting software in production. A scheme gives me mentors, rotations and exposure to those habits early, which would take much longer to pick up alone. I'm also drawn by the chance to work out which area suits me best, whether that's back end, data or platform work, before I specialise.

Common mistake to avoid: Saying you only want the salary or brand name; Giving a generic answer with no personal story

Want the rest?

Full model answers, key points and common mistakes for all 25 questions are on the Graduate Software Engineer interview questions page. The first five are free, no sign-up needed.