Dogecoin is among the top three virtual currencies, along with Bitcoin and Litecoin. It also has the least existing infrastructure of the three. Currently, there does not exist any credible fiat to Dogecoin exchange.
MoonX allows traders to buy and sell Dogecoin directly with USD and other fiat currencies. The exchange is built with ultra-low latency in mind, and is fully generalized to support trading for any arbitrary currency pair within minutes.