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.
ExchangeRate-API - An easy to use, free & reliable Exchange Rate API trusted by tens of thousands of developers since 2010!
FXPlus - Forex Exchange and Trading
xChangeApi - Easy to use, free live updated foreign exchange rates API
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.
Kantox - Kantox is a fintech company offering FX management solutions.