In this guide
Role-specific resume and interview guides
Software engineer interviews: coding, system design and how to prepare
What software engineering interview stages test, from screening and coding exercises to system design and behavioural rounds, and how to prepare for each.
The common stages and what they test
| Stage | What it tests | How to prepare |
|---|---|---|
| Recruiter or hiring-manager screen | Fit, experience level, logistics | A two-minute summary of your recent work and why this role |
| Coding exercise | Problem solving, code quality, testing | Practise talking through problems aloud in the language you will use |
| System design | Architecture, trade-offs, scale | Practise a structure for open design questions |
| Code review or pairing | Collaboration and reading code | Review real pull requests and explain your comments |
| Behavioural | Ownership, conflict, learning from failure | Prepare stories about incidents, disagreements and decisions |
Companies vary widely. Ask the recruiter what each stage involves, which language or tools you may use, and whether internet access or documentation is allowed. Asking is normal and helps you prepare for the right thing.
Coding exercises: show your reasoning
- Restate the problem and ask about inputs, edge cases and constraints.
- Describe a simple approach first, then improve it if needed.
- Write readable code with sensible names, narrating key decisions.
- Test it with a normal case, an edge case and an empty or invalid input.
- Discuss time and memory trade-offs, and what you would change in production.
Illustrative example
Talking through a problem
- 'Before I code, can I check whether the list can be empty and whether values can repeat?'
- 'A straightforward version sorts first; that is fine for small inputs. If this runs on large streams, I would use a hash map instead.'
- 'Let me test the empty list and a list with one item before we move on.'
System design: a structure for open questions
- Clarify requirements: users, core features, scale and non-functional needs such as latency or availability.
- Sketch the main components and how data flows between them.
- Choose storage and explain why, including consistency trade-offs.
- Identify bottlenecks and failure points, and how you would handle them.
- Say what you would build first and what you would postpone.
Design rounds reward explicit trade-offs more than fashionable components. Relating the design to something you have actually run, including what went wrong, is strong evidence.
Engineering behavioural questions
Prepare four or five stories from your own work: an incident you handled, a technical disagreement, a project that slipped, a time you improved quality or reliability, and something you learned quickly. Engineering interviewers listen for ownership and what you changed afterwards.
Before a technical interview
- I know the format, language and tools allowed for each stage.
- My development environment and camera work, if it is remote.
- I have practised explaining my reasoning aloud.
- I can describe two of my projects in depth, including trade-offs.
- I have questions ready about the team's engineering practices.
Common questions
What if I cannot solve the coding problem?
Keep reasoning aloud, solve a simpler version, and explain what you would try next. Interviewers often value a clear partial approach over a silent attempt.
Should I prepare for take-home tasks differently?
Yes. Ask how much time is expected, keep to it, write a short readme explaining decisions and trade-offs, and include tests.
Put it into practice
See how Luceria helps with thisDrafted with AI assistance and checked against Luceria’s editorial standards. Examples are illustrative, not real people’s results. Spotted something out of date? Tell us.