If you're specifically _not_ looking for react front-end developers, then the on-the-job training for those candidates on the position you're filling _can_ be cost (time) prohibitive in certain orgs to "get up to speed." Likely you should filter those candidates out earlier if that's your case. Sounds like you are, but I'd like to also point out that this strategy has it's own costs.
For example, I would take a react developer with obvious gaps and a strong willingness to learn on my back-end services team over a passable back-end dev who was set in their ways (unwilling/uneager to learn new tech, entrenched opinions stated as fact, etc.)
Naturally, my approach is not a one size fits all situation and a great deal depends on org structure and mentorship opportunities being in place for it to work. The benefit being you avoid monoculture "silos", and have more cross collaboration and transfer opportunities between teams (some may call this "full stack", I wouldn't)
Several high performers on my team are "self-taught", work comfortably across several languages today and can pickup new tech easily. They came in knowing their "one stack" at the time. If they were "bootcampers" or not seems irrelevant and somewhat reductive/offensive.
That said, if the candidate in question shows _no_ understanding of their problem domain, can't reason their way out of a paper bag, and get visibility upset from questions when you try and tease that out, that is a certainly a red flag in my book.
With respect to your example given, however, it could be argued that http details because of the abstractions in place inherent in react, aren't critical domain knowledge for what is essentially a UX dev. If they can ship an experience your users enjoy more than the candidate that can recite the HTTP 1.1 RFC and cannot, then what have you gained in hiring the latter other than maintaining a culture of pedantry?
TL;DR it comes down to how much risk your team is willing to take on, as there's always risk inherent in hiring ANY candidate, including those that don't already check all your boxes in regards to tech know-how. I'm merely stating that by overlooking candidates that don't fit your self-imposed mold, you're likely missing opportunities for rewards that can pay dividends when it does work.
For example, I would take a react developer with obvious gaps and a strong willingness to learn on my back-end services team over a passable back-end dev who was set in their ways (unwilling/uneager to learn new tech, entrenched opinions stated as fact, etc.)
Naturally, my approach is not a one size fits all situation and a great deal depends on org structure and mentorship opportunities being in place for it to work. The benefit being you avoid monoculture "silos", and have more cross collaboration and transfer opportunities between teams (some may call this "full stack", I wouldn't)
Several high performers on my team are "self-taught", work comfortably across several languages today and can pickup new tech easily. They came in knowing their "one stack" at the time. If they were "bootcampers" or not seems irrelevant and somewhat reductive/offensive.
That said, if the candidate in question shows _no_ understanding of their problem domain, can't reason their way out of a paper bag, and get visibility upset from questions when you try and tease that out, that is a certainly a red flag in my book.
With respect to your example given, however, it could be argued that http details because of the abstractions in place inherent in react, aren't critical domain knowledge for what is essentially a UX dev. If they can ship an experience your users enjoy more than the candidate that can recite the HTTP 1.1 RFC and cannot, then what have you gained in hiring the latter other than maintaining a culture of pedantry?
TL;DR it comes down to how much risk your team is willing to take on, as there's always risk inherent in hiring ANY candidate, including those that don't already check all your boxes in regards to tech know-how. I'm merely stating that by overlooking candidates that don't fit your self-imposed mold, you're likely missing opportunities for rewards that can pay dividends when it does work.