Here below you can find an example of how you can send an email using SMTP Relay (SMTP+) from your client application.
It is a PHP snippet that requires PHPMailer and the credentials of a SMTP+ user.
PHP - Sending email using SMTP+
<?php
//########################################################
//Include the PHPmailer class.
//
//PHPmailer allows you to create and transport an email an email message.
//The PHPmailer class is available at this address:
//https://github.com/PHPMailer/PHPMailer/
//########################################################
require_once "class.phpmailer.php";
$EmailMessage = new PHPmailer();
$EmailMessage->SetLanguage('en','language/'); //Define the language
//**********************************************
//SMTP configuration
//**********************************************
$EmailMessage->IsSMTP(); //Specify usage of SMTP Server
$EmailMessage->Host = "in.smtpok.com"; //SMTP+ Server address
$EmailMessage->Port="25"; //SET the SMTP Server port
$EmailMessage->Username = "smtpplus_username"; //SMTP+ authentication: username
$EmailMessage->Password = "smtpplus_password"; //SMTP+ authentication: password
$EmailMessage->SMTPAuth = true; //Authentication required
//**********************************************
//Email data
//**********************************************
$EmailMessage->IsHTML(true); //Set the email format
$EmailMessage->FromName= "myname"; //From: display name
$EmailMessage->From="sender_address@domain.com"; //From: email address
$EmailMessage->AddAddress("recipient_address@domail.com"); //Add one or more recipients
$EmailMessage->Subject="My first email sent via SMTP+"; //Set the email subject
$EmailMessage->Body="<b>Hello,<b><br/>This is my first email."; //Set the email body
$EmailMessage->AltBody="Hello, This is my first email.."; //Set the email text part
//**********************************************
//Send the email
//**********************************************
if(!$EmailMessage->Send())
{
echo "<h1>Error sending the email.</h1>"; //Email was not sent
}
else
{
echo "Email has been sent"; //Mail sent
}
?>