Hi. I'm looking for a library that can create keys/addresses and create/sign transactions of multiple coins, preferably in c/c++, python or javascript for a web/RPC app. Are there any options?

I found nothing in c/c++, found "bitwasp" in php, but only supports a handful of coins (I'm looking for the top ~20), and I'm having a hard time finding anything else. Is this why most applications usually support only Bitcoin? It seems like most of the currencies (except maybe IOTA and Ethereum) can be abstracted behind the same interface

Hi, I'd like to buy 0.05 btc worth, how does it work?