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Sending Emails

Arkos provides a powerful EmailService class that delivers a robust and flexible solution for handling email-related tasks in your application with a simple, unified API.

The EmailService is built on top of Node.js's nodemailer library, providing a streamlined interface while maintaining flexibility. Key features include:

  • Simple, unified API with a single versatile send method
  • Support for both default and custom SMTP configurations
  • HTML to plain text conversion
  • Connection verification
  • Easy configuration updates
  • Multiple instance support

You can read more about nodemailer itself at https://www.npmjs.com/package/nodemailer

Configuration​

The EmailService uses these arkosConfig variables for its default configuration:

arkos.init({
  email: {
    host: process.env.EMAIL_HOST,
    port: process.env.EMAIL_PORT,
    secure: process.env.EMAIL_SECURE,
    auth: {
      user: process.env.EMAIL_USER,
      pass: process.env.EMAIL_PASSWORD,
    },
    name: process.env.EMAIL_NAME,
  },
  // other configs
});
info

You can pass these values directly if you want, but the best community practice is to use environment variables.

The email configuration in Arkos allows you to set up email functionality through the emailService. Here's an explanation of each parameter:

host​

  • The URL or hostname of your email provider's SMTP server
  • Example: smtp.gmail.com, smtp.office365.com, smtp.mailgun.org
  • Required parameter

port​

  • The SMTP port number for your email provider
  • Optional parameter with a default value of 465 (secure SMTP)
  • Common alternatives: 587 (TLS), 25 (standard/insecure)

secure​

  • Boolean flag indicating whether to use a secure connection (TLS/SSL)
  • Optional parameter with a default value of true
  • Set to false when using port 587 (TLS)

auth​

  • Object containing authentication credentials:
    • user: The email address used for authentication with the SMTP server
    • pass: Your SMTP password or authentication token for the email account
  • Required parameter

name​

  • The display name that appears alongside your email address
  • Optional parameter
  • Example: If set to "Your App Team", emails will appear from "Your App Team <user@example.com>"

This configuration enables the built-in email service in Arkos for sending emails from your application.

Basic Usage​

Sending an Email with Default Configuration​

// src/modules/auth/auth.middlewares.ts
import { emailService } from "arkos/services";
import { ArkosRequest, ArkosResponse, ArkosNextFunction } from "arkos";
import { catchAsync } from "arkos/error-handler";

export const afterSignup = catchAsync(
  async (req: ArkosRequest, res: ArkosResponse, next: ArkosNextFunction) => {
    const result = await emailService.send({
      to: "recipient@example.com",
      subject: "Welcome to Our Platform",
      html: "<h1>Welcome!</h1><p>Thank you for registering.</p>",
    });

    console.log(`Email sent successfully! Message ID: ${result.messageId}`);

    next();
  }
);

Email Options​

type EmailOptions = {
  from?: string; // Optional: Overrides the default sender
  to: string | string[]; // Single recipient or array of recipients
  subject: string; // Email subject line
  text?: string; // Optional: Plain text version (auto-generated from HTML if not provided)
  html: string; // HTML content of the email
};

Advanced Usage​

Sending with Custom SMTP Configuration​

You can send an email using different credentials without changing the default configuration:

await emailService.send(
  {
    to: "client@example.com",
    subject: "Your Invoice",
    html: "<p>Please find your invoice attached.</p>",
  },
  {
    host: "smtp.yourcompany.com",
    port: 587,
    secure: false,
    auth: {
      user: "billing@yourcompany.com",
      pass: "billingPassword",
    },
  }
);

Creating Additional Email Service Instances​

If you need to use multiple email configurations in your application:

import { EmailService } from "arkos/services";

const marketingEmailService = EmailService.create({
  host: "smtp.marketing-provider.com",
  port: 587,
  secure: false,
  auth: {
    user: "marketing@yourcompany.com",
    pass: "marketingPassword",
  },
});

// Later in your code
await marketingEmailService.send({
  to: "prospects@example.com",
  subject: "Special Offer",
  html: "<h1>Limited Time Offer!</h1><p>Check out our new products...</p>",
});

Updating Configuration​

If you need to switch to a different email account for an existing service instance:

emailService.updateConfig({
  host: "smtp.newprovider.com",
  port: 587,
  secure: false,
  auth: {
    user: "new@example.com",
    pass: "newPassword",
  },
});

Connection Verification​

The connection is automatically verified before sending emails with custom configuration, but you can also manually verify it:

// In some async function
const isConnected = await emailService.verifyConnection();

if (isConnected) {
  console.log("SMTP connection is working correctly");
} else {
  console.log("SMTP connection failed - please check your credentials");
}

You can skip connection verification when sending emails by passing a third parameter:

await emailService.send(
  {
    to: "client@example.com",
    subject: "Quick notification",
    html: "<p>This is an urgent notice.</p>",
  },
  undefined, // Use default connection
  true // Skip verification to send faster
);

Best Practices​

  1. Use Templates: Instead of inline HTML, use template engines like Handlebars or EJS.

  2. Handle Errors: Always use catchAsync when sending emails during requests or try/catch blocks for other scenarios. See catchAsync Function Guide.

  3. Security: Never hardcode email credentials in your code.

  4. Rate Limiting: Implement rate limiting for bulk emails to prevent IP blacklisting.

  5. Testing: Create a mock transporter for testing without sending real emails.

Diving Deeper​

For more in-depth understanding of the EmailService class see The EmailService Class API Reference