I am personally not a huge fan, but like many statically-typed functional languages, Haskell is great for
- creating new programming languages and DSLs
- problems in finance, energy, medicine, etc., that are more correctness-sensitive than performance-sensitive (it is widely used in Bitcoin brokerages / exchanges / etc, and in general blockchain technologies)
- highly-concurrent scenarios that would otherwise involve a lot of painful management of threads/locks/etc
- creating new programming languages and DSLs
- problems in finance, energy, medicine, etc., that are more correctness-sensitive than performance-sensitive (it is widely used in Bitcoin brokerages / exchanges / etc, and in general blockchain technologies)
- highly-concurrent scenarios that would otherwise involve a lot of painful management of threads/locks/etc
Facebook’s Haxl is a good example of software that uses Haskell effectively: https://engineering.fb.com/2014/06/10/web/open-sourcing-haxl...