The API is free for personal or commercial use with attribution required.

The Currency conversion is provided by currencies.zone.

Usage

http://api.currencies.zone/v1/quotes/{target}/{format}?quantity={quantity}&key={YOUR_KEY}
http://api.currencies.zone/v1/quotes/THB/EUR/json?qty=3&k={YOUR_KEY}
{
"result": {
"updated": "2017-07-25T12:53:00",
"source": "THB",
"target": "EUR",
"value": 0.0261,
"quantity": 3.0,
"amount": 0.07829
},
"status": "OK"
}