If you have tried to search for currency exchange rate APIs, chances are that it has not been a smooth experience. While there are plenty of currency conversion websites, getting access to up-to date exchange rates to power your financial applications has usually gotten stalled due to high usage fees. Some services charge in the hundreds of dollars per year to get access to these rates. If CurrencyBot and the Open Source Exchange Rates API project has its way, this could be a problem of the past.
The goal of the Open Source Exchange Rate project is to make itself a reliable source of exchange rates that is available for free and with no usage limits. The CurrencyBot makes all of this possible in the following manner. It wakes up every hour, uses the Google Calculator API to collect the exchange rates and publishes the JSON feed to a public Github Code repository.
There are two JSON feeds:
In case you are looking at making cross domain/AJAX requests, the same data is hosted for you with the right Access-Control headers at openexchangerates.org. The base currency currently is the USD and the rates for the other currencies are based on that. There are plans to support a different base currency in the future. The developers have made sure that historical data for the rates is also available by date. For full documentation, refer to the Project page.
The Open Source Exchange Rates project seems like a great breakthrough. Developers looking for Proof of Concepts, Mashup applications which are non-commercial in nature will benefit tremendously from this API.