Need API for currency converting [closed]

Question

Please advice API for currency converting which returns JSON or small size html. I use http://www.google.com/finance/converter?a=1&from=RUB&to=USD that returns HTML of 11 kb. I use it in my iOS app.

Thanks in advance!

Answer 1

I use a php-class to convert currency rates:

/**
 * Yahoo currency rate import class
 *
 * @author     Felix Geenen (http://www.geenen-it-systeme.de)
 * @version    1.0.3
 */
class Yahoofinance {
    public static $_url = 'http://download.finance.yahoo.com/d/quotes.csv?s={{CURRENCY_FROM}}{{CURRENCY_TO}}=X&f=l1&e=.csv';
    public static $_messages = array();
 
    /*
     * converts currency rates
     *
     * use ISO-4217 currency-codes like EUR and USD (http://en.wikipedia.org/wiki/ISO_4217)
     *
     * @param currencyFrom String base-currency
     * @param currencyTo String currency that currencyFrom should be converted to
     * @param retry int change it to 1 if you dont want the method to retry receiving data on errors
     */
    public static function _convert($currencyFrom, $currencyTo, $retry=0)
    {
        $url = str_replace('{{CURRENCY_FROM}}', $currencyFrom, self::$_url);
        $url = str_replace('{{CURRENCY_TO}}', $currencyTo, $url);
 
        try {
            $handle = fopen($url, "r");
 
            if($handle !== false) {
                $exchange_rate = fread($handle, 2000);
     
                # there may be spaces or breaks
                $exchange_rate = trim($exchange_rate);
                $exchange_rate = (float) $exchange_rate;
     
                fclose($handle);
     
                if( !$exchange_rate ) {
                    echo 'Cannot retrieve rate from Yahoofinance';
                    return false;
                }
                return (float) $exchange_rate * 1.0; // change 1.0 to influence rate;
            }
        }
        catch (Exception $e) {
            if( $retry == 0 ) {
                # retry receiving data
                self::_convert($currencyFrom, $currencyTo, 1);
            } else {
                echo 'Cannot retrieve rate from Yahoofinance';
                return false;
            }
        }
    }
}

Answer 2

free.currencyconverterapi.com returns results in JSON format.

The web service also supports JSONP. The API is very easy to use, and it lets you convert one currency to another.

Disclaimer, I'm the author of the website.

A sample conversion URL is: http://free.currencyconverterapi.com/api/v6/convert?q=USD_PHP&compact=ultra&apiKey=sample-api-key which will return a value in json format, e.g. {"USD_PHP":51.459999}