Send Email to Multiple Recipients

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,"https://insprl.com/api/email/send-to-batch");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, 
   array( 'Authorization: {CLIENT_KEY}'
));
curl_setopt($ch, CURLOPT_POSTFIELDS, 
http_build_query(
array(
   'client_id'	=> '{CLIENT_ID}',
   'sender_email'	=> 'marketing@website.com',
   'recipient_email'	=> 'customer1@example.com, customer2@example.com',
   'subject'	=> 'Welcome to My Site',
   'mail_body'	=> 'Dear Customer, Write you message here.',
   'campaign_name'	=> 'Marketing Campaign 1',
   'files'	=> 'https://insprl.com/resource-doc/SPRL-SAMPLE-API-DOCUMENT.pdf,https://insprl.com/uploads/logo/logo-300.png',
)
));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close ($ch);

{
"code":"100",
"message":"success",
"data":{
   "queue_id":"55610789",
   "status":"accepted",
   "msg":"Mail Queued"
}
}