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.
XE.com - XE.com Inc. (XE) is a Canadian online foreign exchange services company.
exchangeratesapi.io - Foreign exchange rates API with currency conversion.
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
xChangeApi - Easy to use, free live updated foreign exchange rates API
Valuta+ - Valuta+ is a super simple & free currency converter. The interface is fast and makes you convert exchange rates very easily. This app have more than 160+ currencies for you and is always updated.