Why F#?

Our shop converted 6 years ago, from C# to exclusively F#. I also author and maintain some packages (falco, donald, validus and others). The language is tough to learn if you're coming from a C-style language. But worth the effort and experience. It's extremely concise a true delight to build programs in that are fast, robust and durable.

There are a few drawbacks, depending on your perspective:

- compilation is slower than c# and hot reload isn't supported (it's in progress)

- there are very few opportunities to use it professionally

- hiring devs can be challenging

Hiring devs is perfectly fine if you don't look for F# skills - just hire generally smart people, and allow them 1-2 weeks to get comfortable with F#. Make them just solve problems from project euler or something.

For those who have already done functional programming, they wont take more than 2 days to start getting productive. For those who have written a lot of code, it will take them ~2 weeks to pick up functional thinking.

Anyone who is still uncomfortable with F# after 1 month - well that's a strong signal that the dev isn't a fast learner.

Additionally, I've never had anyone reject our job offer because we do F#. I'm sure a whole bunch of people might only be looking for python or javascript jobs, but that's fine because I'm not looking for them. I always have more people who I want to hire but I can't due to budget constraints.

Source: direct experience - I run a pure F# company with a team size of ~80.