$service_url = 'https://example.com/something/something.json';
$curl = curl_init($service_url);
curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($curl, CURLOPT_USERPWD, "username:password"); //Your credentials goes here
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $curl_post_data);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false); //IMP if the url has https and you don't want to verify source certificate

$curl_response = curl_exec($curl);
$response = json_decode($curl_response);
curl_close($curl);

var_dump($response);