Conversión de Monedas

var client = new RestClient("https://api.mobbex.com/p/currency/convert?from=USD&to=ARS&total=100");
client.Timeout = -1;
var request = new RestRequest(Method.GET);
request.AddHeader("x-api-key", "zJ8LFTBX6Ba8D611e9io13fDZAwj0QmKO1Hn1yIj");
request.AddHeader("x-access-token", "d31f0721-2f85-44e7-bcc6-15e19d1a53cc");
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

var xhr = new XMLHttpRequest();
xhr.withCredentials = true;

xhr.addEventListener("readystatechange", function() {
  if(this.readyState === 4) {
    console.log(this.responseText);
  }
});

xhr.open("GET", "https://api.mobbex.com/p/currency/convert?from=USD&to=ARS&total=100");
xhr.setRequestHeader("x-api-key", "zJ8LFTBX6Ba8D611e9io13fDZAwj0QmKO1Hn1yIj");
xhr.setRequestHeader("x-access-token", "d31f0721-2f85-44e7-bcc6-15e19d1a53cc");

xhr.send();

<?php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.mobbex.com/p/currency/convert?from=USD&to=ARS&total=100',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 0,
  CURLOPT_FOLLOWLOCATION => true,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => 'GET',
  CURLOPT_HTTPHEADER => array(
    'x-api-key: zJ8LFTBX6Ba8D611e9io13fDZAwj0QmKO1Hn1yIj',
    'x-access-token: d31f0721-2f85-44e7-bcc6-15e19d1a53cc'
  ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

{
    "result": true,
    "data": {
        "from": "USD",
        "to": "ARS",
        "total": 100,
        "result": 9761,
        "rate": 97.61
    }
}