Setup SMTP Keys

Generate SMTP credentials for connected email accounts to use with traditional email clients

Generate SMTP credentials to use your connected email accounts with traditional email libraries like Nodemailer, PHPMailer, or built-in SMTP clients.

SMTP Credentials: Use your connected Gmail/Outlook accounts with any SMTP-compatible email library or application.

Generate SMTP Credentials

Access SMTP Section

Sign in to dash.keplars.com
Navigate to SMTP Credentials in the sidebar
Click Generate SMTP Credentials

Configure Credentials

Select your connected email account
Enter a descriptive name (e.g., "Production App")
Click Generate

Save Credentials

Important: Copy your SMTP credentials immediately - they're shown only once.

Copy the SMTP username and password
Store them securely in your environment variables
Click Done

Connection Settings

Use these settings with any SMTP client:

Host: smtp.keplars.com
Port: 587 (recommended - industry standard)
      or 2525 (legacy - will be deprecated)
Security: STARTTLS
Username: [Your generated username]
Password: [Your generated password]

Port 587 is the industry-standard SMTP submission port and is recommended for all new integrations. Port 2525 is supported for backward compatibility but will be deprecated in the future.

SMTP Capabilities & Limitations

SMTP vs API Features:

✅ SMTP Supports:

Raw email content (subject, body, HTML)
Custom sender display names (e.g., From: John Doe <[email protected]>)
Multiple recipients (To, CC, BCC)
File attachments
Custom headers

❌ SMTP Does NOT Support:

Email templates - Templates are only available via the REST API
Template parameters and dynamic content
Advanced features like AI-generated content

When to use SMTP:

Legacy applications that can't make HTTP requests
Existing codebases using SMTP libraries
Drop-in replacement for traditional SMTP servers

When to use the API:

New integrations and modern applications
When you need email templates
Better error handling and debugging
Advanced features and analytics

Code Examples

const nodemailer = require('nodemailer');

const transporter = nodemailer.createTransporter({
  host: 'smtp.keplars.com',
  port: 587,
  secure: false, // Enable STARTTLS (upgrades connection to TLS)
  auth: {
    user: process.env.KEPLERS_SMTP_USERNAME,
    pass: process.env.KEPLERS_SMTP_PASSWORD
  }
});

async function sendEmail() {
  await transporter.sendMail({
    from: '[email protected]',
    to: '[email protected]',
    subject: 'Hello from Nodemailer',
    text: 'This email was sent using SMTP credentials'
  });
}

sendEmail()
  .then(() => console.log('Email sent successfully'))
  .catch(error => console.error('Error:', error));

Install:

npm install nodemailer

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import os

# SMTP Configuration
smtp_username = os.getenv('KEPLERS_SMTP_USERNAME')
smtp_password = os.getenv('KEPLERS_SMTP_PASSWORD')

# Create message
message = MIMEMultipart()
message['From'] = '[email protected]'
message['To'] = '[email protected]'
message['Subject'] = 'Hello from Python'

body = 'This email was sent using SMTP credentials'
message.attach(MIMEText(body, 'plain'))

# Send email
try:
    server = smtplib.SMTP('smtp.keplars.com', 587)
    server.starttls()  # Enable STARTTLS encryption
    server.login(smtp_username, smtp_password)
    server.send_message(message)
    server.quit()
    print('Email sent successfully')
except Exception as e:
    print(f'Error: {e}')

Note: smtplib is part of Python's standard library (built-in since Python 2.6), so no installation is required.

<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

require 'vendor/autoload.php';

$mail = new PHPMailer(true);

try {
    // Server settings
    $mail->isSMTP();
    $mail->Host = 'smtp.keplars.com';
    $mail->SMTPAuth = true;
    $mail->Username = getenv('KEPLERS_SMTP_USERNAME');
    $mail->Password = getenv('KEPLERS_SMTP_PASSWORD');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port = 587;

    // Recipients
    $mail->setFrom('[email protected]');
    $mail->addAddress('[email protected]');

    // Content
    $mail->isHTML(false);
    $mail->Subject = 'Hello from PHPMailer';
    $mail->Body = 'This email was sent using SMTP credentials';

    $mail->send();
    echo 'Email sent successfully';
} catch (Exception $e) {
    echo "Error: {$mail->ErrorInfo}";
}
?>

Install:

composer require phpmailer/phpmailer

package main

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

func main() {
    // SMTP Configuration
    smtpHost := "smtp.keplars.com"
    smtpPort := "587"
    username := os.Getenv("KEPLERS_SMTP_USERNAME")
    password := os.Getenv("KEPLERS_SMTP_PASSWORD")

    // Message
    from := "[email protected]"
    to := []string{"[email protected]"}
    subject := "Subject: Hello from Go\n"
    body := "This email was sent using SMTP credentials"
    message := []byte(subject + "\n" + body)

    // Authentication
    auth := smtp.PlainAuth("", username, password, smtpHost)

    // Send email with STARTTLS
    err := smtp.SendMail(
        smtpHost+":"+smtpPort,
        auth,
        from,
        to,
        message,
    )

    if err != nil {
        fmt.Printf("Error: %v\n", err)
        return
    }
    fmt.Println("Email sent successfully")
}

Note: Go's smtp.SendMail automatically uses STARTTLS when available on port 587.

Understanding STARTTLS Security:

The secure: false setting (in Node.js/similar libraries) enables STARTTLS encryption, which is the recommended security method for port 587:

Connection Flow: Starts as plaintext → Client sends STARTTLS command → Connection upgrades to TLS encryption → All data (credentials, emails) transmitted securely
Industry Standard: Port 587 with STARTTLS is the modern standard for email submission (RFC 6409)
Not Insecure: Despite the name, secure: false enables encryption via STARTTLS upgrade

Alternative: secure: true (Port 465)

Uses implicit TLS (connection encrypted from start)
Legacy approach, less commonly used
Keplers supports port 587 with STARTTLS only

Environment Variables

Store your credentials securely:

# .env file
KEPLERS_SMTP_USERNAME=your_generated_username
KEPLERS_SMTP_PASSWORD=your_generated_password

Manage Credentials

View Credentials

In your dashboard's SMTP Credentials section:

View all your SMTP credentials
Check usage statistics
Monitor last activity

Update Credentials

Edit: Change name or settings
Deactivate: Temporarily disable
Delete: Permanently remove

Security

Best Practices:

Never commit SMTP credentials to code repositories
Use environment variables
Rotate credentials regularly
Monitor usage for suspicious activity

Next Steps

Send Emails - Learn about API-based email sending
Examples - See SMTP integration examples for your language
Webhooks - Get delivery notifications

Your SMTP credentials are ready. Use them with any SMTP-compatible email library to send emails through your connected accounts.

Setup SMTP Keys

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