[ydt]

Not heresy at all. Everyone I know that has used it, including myself, really likes it. Yet no one I know has ever used it a real production environment. I guess it has some traction in financial circles, but that's about it. Maybe .NET going cross-platform will lead to some adoption.

[jackfoxy]

We at Tachyus use it as the main server-side language in our production environment. Also on Linux/Mono. Jet uses it, and they were bought by WalMart for > $1B. There is no problem running in production. In fact, there is a noticeable lack of problems running in production.

[neilsimp1]

I'm pretty sure https://jet.com/ uses F# for their price calculations.

[lzybkr]

It's used in production for Microsoft Security Risk Detection - here is a good blog post describing how F# is used: https://blogs.msdn.microsoft.com/dotnet/2016/12/13/project-s...

[Nelkins]

Elastic uses it for their Windows/.NET pipeline[1]!

And Kaggle, and Credit Suisse, and...[2]

[1] https://www.elastic.co/blog/solidifying-releases-with-fsharp...

[2] http://fsharp.org/testimonials/

[gecko]

Kiln, Fog Creek's old Git/Mercurial hosting environment, had major components written in F#. Those components honestly were probably the only genuinely bug-free parts of the code base (though I think that had as much to do with developers self-selecting to work on those areas as it did to do with using F# as such).

[DanielBMarkham]

It's used in production in a ton of places, although that's only 1-2% probably. Still a lot. And the numbers are growing.

[platz]

same thoughts; some legacy things irk me a bit though, like the inefficiency of async