FXPlus - Forex Exchange and Trading
ExchangeRate-API - An easy to use, free & reliable Exchange Rate API trusted by tens of thousands of developers since 2010!
mbox - Mbox is the based on the technology of sandbox and is primarily deployed for the purpose of configuration or carry on those activities on the system that are suspicious are in nature.
Fixer.io - Fixer provides a free, simple, and lightweight API for current and historical foreign exchange rates and currency conversion. The API tracks rates published daily by the European Central Bank.
CurrencyXchanger - Currency Exchange Software for Money Service Businesses
xChangeApi - Easy to use, free live updated foreign exchange rates API