What a live coding interview actually tests
A live coding interview asks you to write working code in real time, usually on a shared screen or collaborative editor, while explaining your reasoning as you go. Interviewers are assessing your live problem-solving process, code structure and clarity, and how you handle mistakes and edge cases under real observation, not just whether the final code compiles and runs correctly.
How to approach the exercise
Clarify requirements and constraints before writing any code, including asking about expected input sizes, edge cases, and any specific language or style preference. Talk through your approach and reasoning before and while coding, write clean, readable code even under time pressure, and test your solution against a few example cases yourself before declaring it finished, since interviewers specifically watch whether you self-check your own work.
Common mistakes to avoid
Jumping straight into coding without first explaining your planned approach is one of the most common mistakes, since it leaves the interviewer unable to follow your reasoning and increases the risk of solving the wrong problem. Ignoring edge cases entirely, and reacting defensively or going silent when the interviewer points out a bug, are also significant, avoidable errors; treating a bug as a normal, expected part of the process and calmly debugging it out loud is a much stronger response.
How to prepare
Practise solving problems out loud under timed conditions, ideally using the same tools (a shared editor, a specific language) you expect to use in the real interview. Review common data structure and algorithm patterns relevant to the role, and practise deliberately debugging out loud when your code does not immediately work, since this is a realistic part of almost every live coding interview.