This interested me too so I looked through the source to find out. NFHTTP seems to add 2 clients of its own, one that uses NSURL (for Apple) and another that uses CURL (for Linux). Everything else (WinHTTP, UWP, and the fallback Boost Asio client) simply call down and use the cpprestsdk implementations directly.

Seems like this library offers less itself than it says on the tin, given that 3/5 of its native impls just call down to cpprestsdk. It's a pity that spotify didn't simply add CURL and NSURL clients to cppressdk - that would have been far more useful IMO.

Dependencies

    C++ REST SDK
    curl

This is also my question. Having C ++ REST SDK as a dependency not only does not answer that but it adds additional questions. Also the duplicate use of libs (C ++ REST SDK already has JSON support).