$url='http://localhost/smtpmailer/index.php';
$param=array(
    'host'=>'smtp.163.com',
    //'port'=>456,
    'username'=>'发送账号',
    'password'=>'发送账号的密码或者授权码',
    'from'=>'发送邮箱',
    'to'=>'接收邮箱',
    'subject'=>'邮件标题',
    'message'=>'邮件内容<b>hello word</b>',
    
    'is_html'=>1,
);
$res = curlget($url,$param,'POST');
$res = json_decode($res,1);
var_export($res);

开源地址：https://gitee.com/web/smtpmailer