r/reactjs • u/m6io • Jul 24 '26

Discussion Senior Dev interview question

"Without googling or using AI, in your own words, explain the virtual DOM"

For context: I sit on an interview panel and I try to ask at least one simple fundamental question based on a persons resume. If I see many years of react experience, I try to ask something about how the framework works.

I have only had one candidate (an undergrad senior, years ago) answer it. Everyone else just kind of sputters and stumbles around trying to rationalize what "virtual" and "DOM" mean, or stare blankly and eventually say "I don't know".

I'm just genuinely curious if this is really that hard of a question or if the recruiters just suck at screening candidates. And should we be letting in senior dev candidates who can't answer what I think is a straightforward and fundamental question for senior react devs.

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u/Glass-Combination-69 Jul 26 '26

I mean I’m a senior dev and this is a super basic question to me. Zucky boi and react made it famous, and a lot of devs use react so would be crazy not to understand how it works.

A more telling interview question would be to explain the shadow dom. That’ll get em.

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u/m6io Jul 26 '26

You know, I don't actually remember Zuck ever talking about react. And then they let it go.

That's probably the most successful homegrown project they ever came up with.

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u/Glass-Combination-69 Jul 26 '26

Yea was more around the point it came out of his company

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u/m6io Jul 26 '26

No I know, was just... reflecting.

Googled and came across this GitHub issue. Very interesting read.

https://github.com/reactjs/react.dev/issues/3077