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.

Avatrade - Avatrade is an online and advanced FX & CFD broker that provides personal investment and trading facilities with the help of currency pairs, cryptocurrencies, commodities & indices as well.

Open Exchange Rates - Free, hourly-updated exchange rates - a simple, accurate, open-source JSON API. Free for personal use, a bargain for everybody else.

finbox.io - Online investing tools that makes it faster & easier to find undervalued stocks.

Currencyapi.com - Currencyapi.com is a free, reliable & feature complete currency exchange rates API. 170+ world currencies & 60 second update rate.

FXCM - FXCM is a UK-based Forex Capital Market that offers forex and CFDs trading and a part of Leucadia that is a diversified holding company.