[Xixi]

There's another point of view: that by targeting people who either know, or are interested in learning F#, or any other less popular language (like Rust, Erlang, Julia, etc.), you massively increase the quality of your applicant pool.

Developers that just want to pay the bills learn the popular languages: Python, javascript, Java, C#, Swift, etc. Developers who plays with (or maybe find little projects to do with) the like of F# are statistically more likely to care about their craft, even if they don't necessarily have the possibility to use these at their current jobs.

If someone contact you specifically because they want to use an FP language, but they can't at their current job, it's a very good sign. Of course if you limit yourself to something like: 5 years of experience writing F# in insert field of interest here, it's going to be very tough to hire anyone...

[ablekh]

Generally, I agree with you, except for the argument that developers who play with (or do projects using) less popular languages "are statistically more likely to care about their craft" (do you have any data supporting this claim?). Being curious, while certainly a valuable trait, is not equivalent to "being caring" about some craft - it is a nice addition to the package. However, it is a bit more nuanced than that. For example, success or failure in using this strategy depends on startup's stage, funding, roadmap, team size, engineering culture as well as current or potential use of microservices architecture, which gives us much greater flexibility in a relevant technology stack selection.