WhatsApp OTP for India.
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var options = new RestClientOptions("https://app.authyo.io")
{
  MaxTimeout = -1,
};
var client = new RestClient(options);
var request = new RestRequest(
  "/api/v1/auth/sendotp?to=&expiry=&otpLength&authWay&otp",
  Method.Get
);
request.AddHeader("clientId", "");
request.AddHeader("clientSecret", "");
request.AddHeader("origin", "");
RestResponse response = await client.ExecuteAsync(request);
Console.WriteLine(response.Content);

<?php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL            => 'https://app.authyo.io/api/v1/auth/sendotp'
                          . '?to=&expiry=&otpLength=undefined'
                          . '&authWay=undefined&otp=undefined',
  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(
    'clientId: ',
    'clientSecret: ',
    'origin: '
  ),
));

$response = curl_exec($curl);
curl_close($curl);
echo $response;

import http.client

conn = http.client.HTTPSConnection("app.authyo.io")
payload = ''
headers = {
  'clientId': '',
  'clientSecret': '',
  'origin': ''
}
conn.request("GET",
  "/api/v1/auth/sendotp?to=&expiry=&otpLength=null&authWay=null&otp=null",
  payload, headers)
res = conn.getresponse()
data = res.read()
print(data.decode("utf-8"))