What an unstructured interview actually is
An unstructured interview has no fixed set of questions asked identically to every candidate; instead, it flows more like a genuine conversation, often following whatever the interviewer finds interesting in your background or answers. Smaller companies, senior hires, and founder-led interviews use this format more often than large, process-driven employers, since it prioritises genuine rapport and judgement over standardised comparison.
Why this format is genuinely harder to prepare for
Without a predictable question list, you cannot simply rehearse fixed answers to expected prompts the way you would for a structured competency interview. The real skill is having a small set of strong, flexible stories and facts about yourself that you can steer naturally into almost any conversational direction, rather than a rigid script that breaks down the moment the conversation goes somewhere unexpected.
How to prepare
Prepare three or four strong, detailed stories from your experience that each demonstrate multiple different strengths, so you can adapt which angle you emphasise depending on where the conversation goes. Research the company and interviewer thoroughly, since unstructured interviews often follow the interviewer's own curiosity, and be ready to ask genuine, specific questions yourself, since this format rewards real engagement over passive question-answering.