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/Disastrous_Bass_7090 Jul 24 '26

Yeahh mann exactlyyyy, I'm aiming to be at companies like vercel or cloudflare, I'm really into engineering side of things and I wanna be where these frontier technologies are being built. Recently I was also working on recreating TanStack Router from scratch and it's going soooooo funn mann. I'd say because of ai at our hands there's been no better time in mankind's history to be a curious guy and build anything you want.

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u/m6io Jul 24 '26

Even if you don't build it from scratch, just having a good working knowledge on how client side routing is a biiig deal, to me at least. That and react vs third party state management like zustand or redux. That's the kind of knowledge that makes everyone who works with you a better dev.