How much should I practise coding problems?

Enough to be fluent in your chosen language under mild pressure. For most roles, two focused weeks beats months of grinding, and talking out loud while solving matters more than volume.

Which language should I use?

The one you are fastest in, unless the advert specifies otherwise. Fluency beats matching their stack in a timed exercise.

Do I need system design for a junior role?

Rarely as a separate round, though you may get a scaled-down design discussion. It becomes standard from mid-level upwards.

Say what you have tried, what you suspect, and what you would look up. Interviewers are allowed to help, and how you ask is part of the assessment.

Software engineer interview questions and preparation

A software engineering interview usually has three assessed parts: a coding exercise, a design discussion scaled to your level, and a behavioural round. Coding rounds score your reasoning out loud at least as much as the final solution.

Written by Ace Editorial · Published 23 September 2026 · Last updated 23 September 2026

What are the usual stages of a software engineering interview?

A recruiter screen, a technical screen or take-home, one or two coding interviews, a system design round for mid-level and above, and a behavioural or values round.

Smaller companies often compress this into a take-home plus one long on-site conversation. The assessment is the same; the packaging is different.

How are coding interviews scored?

On communication, problem decomposition, correctness and testing — usually in that order of leniency. A partly finished solution explained clearly often outscores a silent complete one.

Restate the problem and confirm the constraints before coding
Say the brute-force approach out loud, then improve it
Name the complexity of what you are about to write
Test with an edge case before being asked

How do you prepare for a system design interview?

Practise the same shape every time: requirements, scale estimates, the data model, the components, and then the two or three trade-offs that actually matter.

Interviewers are listening for whether you ask about scale and consistency before drawing boxes. The design that emerges matters less than whether the trade-offs were named.

What behavioural questions do engineers get asked?

A technical disagreement, a production incident you handled, a piece of work you would build differently now, and how you handle code review.

This is the round strong engineers most often underprepare, and it is frequently the one that decides the level you are offered.

How should you handle a take-home exercise?

Timebox it to the stated time, write tests, and include a short README explaining your trade-offs and what you would do with another day.

What questions should you ask an engineering interviewer?

Ask about the path from commit to production, how on-call works, how technical decisions get made, and what the team's biggest source of friction is.

Frequently asked questions

How much should I practise coding problems?: Enough to be fluent in your chosen language under mild pressure. For most roles, two focused weeks beats months of grinding, and talking out loud while solving matters more than volume.
Which language should I use?: The one you are fastest in, unless the advert specifies otherwise. Fluency beats matching their stack in a timed exercise.
Do I need system design for a junior role?: Rarely as a separate round, though you may get a scaled-down design discussion. It becomes standard from mid-level upwards.
What if I get stuck?: Say what you have tried, what you suspect, and what you would look up. Interviewers are allowed to help, and how you ask is part of the assessment.

Don't let the behavioural round be the one you lose

Ace turns the job description and your CV into the non-coding questions you're likely to face, the projects to talk about, and the trade-offs to be ready to defend.

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