Introduction

 https://api.sendpost.io/api/v1

"use strict";

const nodemailer = require("nodemailer");

async function main() {
// create reusable transporter object using the default SMTP transport
let transporter = nodemailer.createTransport({
host: "smtp.sendpost.io",
port: 587,
secure: false, // true for 465, false for other ports
auth: {
user:  "<username>" , // generated ethereal user
pass: "<password>", // generated ethereal password
},
requireTLS: true,
debug: true,
logger: true,
});

// send mail with defined transport object
try {
let info = await transporter.sendMail({
from: 'erlich@piedpiper.com',
to: 'gilfoyle@piedpiper.com',
subject: 'Test Email Subject',
html: '<h1>Hello Geeks!!!</h1>',
});
console.log("Message sent: %s", info.messageId);
} catch (e) {
console.log(e)
}
}

main().catch(console.error);

<?php
// Import PHPMailer classes into the global namespace
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

// Load Composer's autoloader
require 'vendor/autoload.php';

$mail = new PHPMailer(true);

// Settings
try {
$mail->SMTPDebug = SMTP::DEBUG_CONNECTION;                  // Enable verbose debug output
$mail->isSMTP();                                            // Send using SMTP
$mail->Host       = 'smtp.sendpost.io';                     // Set the SMTP server to send through
$mail->SMTPAuth   = true;                                   // Enable SMTP authentication
$mail->Username   = '<username>';                           // SMTP username
$mail->Password   = '<password>';                           // SMTP password
$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;         // Enable implicit TLS encryption
$mail->Port       = 587;                                    // TCP port to connect to; use 587 if you have set `SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS`

//Recipients
$mail->setFrom('erlich@piedpiper.com', 'Erlich');
$mail->addAddress('gilfoyle@piedpiper.com', 'Gilfoyle');

//Content
$mail->isHTML(true);                                  //Set email format to HTML
$mail->Subject = 'Here is the subject';
$mail->Body    = 'This is the HTML message body <b>in bold!</b>';
$mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

$mail->send();
echo 'Message has been sent';

} catch (Exception $e) {
echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}

#!/usr/bin/python3

import sys
import os
import re

from smtplib import SMTP
import ssl

from email.mime.text import MIMEText

SMTPserver = 'smtp.sendpost.io'
PORT = 587
sender =     'erlich@piedpiper.com'
destination = ['gilfoyle@piedpiper.com']

USERNAME = "<username>"
PASSWORD = "<password>"

# typical values for text_subtype are plain, html, xml
text_subtype = 'plain'

content="""\
Test message
"""

subject="Sent from Python"

try:
msg = MIMEText(content, text_subtype)
msg['Subject']= subject
msg['From']   = sender

conn = SMTP(SMTPserver, PORT)
conn.ehlo()
context = ssl.create_default_context()
conn.starttls(context=context)  # upgrade to tls
conn.ehlo()
conn.set_debuglevel(True)
conn.login(USERNAME, PASSWORD)

try:
resp = conn.sendmail(sender, destination, msg.as_string())
print("Send Mail Response: ", resp)
except Exception as e:
print("Send Email Error: ", e)
finally:
conn.quit()

except Exception as e:
print("Error:", e)

package main

import (
"fmt"
"net/smtp"
"os"
)

// Sending Email Using Smtp in Golang

func main() {

username := "<username>"
password := "<password>"

from := "erlich@piedpiper.com"
toList := []string{"gilfoyle@piedpiper.com"}
host := "smtp.sendpost.io"
port := "587" // recommended

// This is the message to send in the mail
msg := "Hello geeks!!!"

// We can't send strings directly in mail,
// strings need to be converted into slice bytes
body := []byte(msg)

// PlainAuth uses the given username and password to
// authenticate to host and act as identity.
// Usually identity should be the empty string,
// to act as username.
auth := smtp.PlainAuth("", username, password, host)

// SendMail uses TLS connection to send the mail
// The email is sent to all address in the toList,
// the body should be of type bytes, not strings
// This returns error if any occured.
err := smtp.SendMail(host+":"+port, auth, from, toList, body)

// handling the errors
if err != nil {
fmt.Println(err)
os.Exit(1)
}

fmt.Println("Successfully sent mail to all user in toList")
}

// implementation 'com.sun.mail:javax.mail:1.6.2'

import java.util.Properties;

import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SMTPConnect {

// This address must be verified.
static final String FROM = "erlich@piedpiper.com";
static final String FROMNAME = "Erlich Bachman";

// Replace recipient@example.com with a "To" address. If your account
// is still in the sandbox, this address must be verified.
static final String TO = "gilfoyle@piedpiper.com";

// Replace smtp_username with your SendPost SMTP user name.
static final String SMTP_USERNAME = "<username>";

// Replace smtp_password with your SendPost SMTP password.
static final String SMTP_PASSWORD = "<password>";

// SMTP Host Name
static final String HOST = "smtp.sendpost.io";

// The port you will connect to on SendPost SMTP Endpoint.
static final int PORT = 587;

static final String SUBJECT = "SendPost SMTP Test (SMTP interface accessed using Java)";

static final String BODY = String.join(
System.getProperty("line.separator"),
"<h1>SendPost SMTP Test</h1>",
"<p>This email was sent with SendPost using the ",
"<a href='https://github.com/eclipse-ee4j/mail'>Javamail Package</a>",
" for <a href='https://www.java.com'>Java</a>."
);

public static void main(String[] args) throws Exception {

// Create a Properties object to contain connection configuration information.
Properties props = System.getProperties();
props.put("mail.transport.protocol", "smtp");
props.put("mail.smtp.port", PORT);
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.debug", "true");
props.put("mail.smtp.auth", "true");

// Create a Session object to represent a mail session with the specified properties.
Session session = Session.getDefaultInstance(props);

// Create a message with the specified information.
MimeMessage msg = new MimeMessage(session);
msg.setFrom(new InternetAddress(FROM,FROMNAME));
msg.setRecipient(Message.RecipientType.TO, new InternetAddress(TO));
msg.setSubject(SUBJECT);
msg.setContent(BODY,"text/html");

// Create a transport.
Transport transport = session.getTransport();

// Send the message.
try {
System.out.println("Sending...");

// Connect to SendPost SMTP using the SMTP username and password you specified above.
transport.connect(HOST, SMTP_USERNAME, SMTP_PASSWORD);

// Send the email.
transport.sendMessage(msg, msg.getAllRecipients());
System.out.println("Email sent!");

} catch (Exception ex) {

System.out.println("The email was not sent.");
System.out.println("Error message: " + ex.getMessage());
System.out.println(ex);
}
// Close and terminate the connection.
}
}