Ask HN: What is your faviorte interview question?

What is the best interview question you have asked/have been asked? It can be either technical or professional. If possible please provide what you are looking for in a response from a candidate.

"What's something that you f*'d up on where you thought you might be fired for it?"

Most any engineer or developer above a junior level position should have at least one of these stories. It also gives you the chance to ask what they learned, how they fixed it, what resources they used, what they did to prevent it in the future, etc, etc, etc. It's also a really humbling moment to have to explain one of your failures and will show you a lot of the person's personality when they're explaining it.

The two big negatives I have seen with this question is either someone becoming combative as you ask more questions, or they go full 'used car salesman.' If either of those happen, you can safely run away screaming from the interview.

This is a gut/understanding question that is best given/asked by another technical user and has been a solid divining rod for interviews that I've done.

I’ve never been worried about being fired for something. Not everyone makes huge fireable mistakes.

Not a single question, but I find the best thing to do is just have a discussion on the software architecture, business problems, organization chart, etc.

When interviewing someone senior, they'll ask back a lot of good questions. The good candidate tries to identify what props up the structure, whether it's code or certain people. Especially in a startup, where sometimes even the code owners forget that they have that big batch of unpaid technical debt.

The passive candidate is usually the ones we try to reject, because when something bad happens, they won't flag it, and when you don't ask them to do things, they just idle instead of improving random things.

When should tests be written for code?

The answer will quickly reveal their methodology and how they approach a project. Generally people don't use tests when prototyping. Some people use tests when things break, others write tests before they code something.

Each type of response is appropriate for a specific role or business and that question is good at determining that.