How do I send data using JSON as output format?
You will need to write a custom module that will select data from the webform tables in the database, encode your response and then call the URL

$crmurl = 'http://www.crmdomain.com/api/datafromdrupal';

if (isset($response)) {
  $json_response = drupal_json_encode($response); /* Pure json encoding */

  $options = array(
             'method' =&gt; 'POST',
             'data' =&gt; $json_response,
             'timeout' =&gt; 15,
             'headers' =&gt; array('Content-Type' =&gt; 'application/x-www-form-
             urlencoded'),);
  $result = drupal_http_request($crmurl, $options);
}