Open Exchange Rates

The Open Exchange Rates API provides easy and fast programmatic access to currency exchange rates for 157 currencies, with advanced features for paying customers (cheaper than every other service!). Open Exchange Rates was designed to provide a free and reliable place for developers to access exchange rates for use in their own apps and projects. Exchange rate data is updated hourly, and historical conversion rates are available as far back as 1999. This API uses RESTful calls in JSON and JSONP, with HTTPS secure connections available.