How to Send Transactional Emails with SMTP2GO in Next.js with Code Examples?

July 18, 2023

In modern web applications, programmatically sending emails plays a crucial role in enhancing user experience, facilitating communication, and driving business growth. As a CTO or technical decision-maker, understanding the importance of email functionality is essential for building robust and user-centric applications.

This technical guide aims to provide CTOs and technical decision-makers like you with a comprehensive understanding of implementing email sending in Next.js applications. It covers the necessary steps, best practices, and optimizations required to ensure seamless and reliable email functionality.

Setting Up Next.js

Before we delve into implementing email sending in Next.js, let's briefly discuss the setup process and familiarize ourselves with the Next.js project structure and foundational concepts. Next.js is a powerful React framework that simplifies the development of server-rendered React applications. To set up a Next.js project, follow these steps:

1. Install Node.js: Ensure that Node.js is installed on your system. You can download and install the latest LTS version from the official Node.js website.

2. Create a New Next.js Project:
Open your terminal or command prompt and run the following command to create a new Next.js project. This command initializes a new Next.js project with the default project structure and installs the necessary dependencies.

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npx create-next-app my-next-project
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3. Explore the Project Structure:
Once the project is created, navigate into the project directory using the following command:

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cd my-next-project
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Inside the project directory, you will find the following important files and folders:

  • `pages`: This folder contains the pages of your application. Each JavaScript file inside this folder represents a unique page.
  • `public`: Place static files (e.g., images, fonts) in this folder, which can be accessed directly from the client-side.
  • `styles`: This folder is used for storing global styles or CSS modules.

4. Start the Development Server:
To start the Next.js development server, run the following command:

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npm run dev
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This command will start the development server, and you can access your Next.js application at `http://localhost:3000`

Selecting an Email Service Provider (ESP)

In this tutorial, we will use SMTP2GO as the email service provider (ESP) for sending emails in Next.js. SMTP2GO offers a reliable SMTP server infrastructure that ensures high deliverability rates and efficient email sending capabilities.

Installing Required Packages

To enable email-sending functionality in your Next.js application using SMTP2GO as the Email Service Provider (ESP), follow these steps:

1. Open your terminal or command prompt and navigate to your Next.js project directory.

Run the following command to install the required packages.

  • The nodemailer package is a widely used module for sending emails from Node.js applications. It provides a simple and flexible API for email-sending operations.
  • The smtp2go-nodejs package is a specific SMTP2GO package that allows integration with SMTP2GO's email delivery service.
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npm install nodemailer smtp2go-nodejs
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Configuring Email Provider Credentials

To send emails using SMTP2GO, you need to acquire the necessary API credentials and configure them securely in your Next.js application. Follow these steps:

  1. Sign up for an SMTP2GO account if you haven't already. Go to the SMTP2GO website and create an account.
  2. Obtain your SMTP2GO API key. This key will be used to authenticate your Next.js application with SMTP2GO.
  3. In your Next.js project, create a .env file in the root directory. Add the following line to the file:
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: Make sure to add `.env` to your `.gitignore` file to prevent the credentials from being committed to version control.

Install the `dotenv` package to load the environment variables from the `.env` file. Run the following command:

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npm install dotenv
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5. Then, in your Next.js application's entry file (e.g., `pages/_app.js`), add the following line at the top to load the environment variables:

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With the SMTP2GO credentials properly configured, your Next.js application is now ready to send emails using SMTP2GO. In the upcoming sections, we will dive into developing a helper function for email sending and integrating it into your Next.js application. Stay tuned to learn the technical details and code examples required for implementing email sending in Next.js using SMTP2GO.

Developing a Helper Function for Email Sending

This helper function will abstract away the email-sending logic, making it easier to send emails from different parts of your application. Let's explore how to implement this functionality using SMTP2GO as the Email Service Provider (ESP).

To use SMTP2GO in your Next.js application, you need to create a helper function that utilizes the nodemailer package and SMTP2GO's SMTP server. Here's an example of how to implement the helper function:


In the same file (`utils/email.js`), add the following code to create a helper function for sending emails using SMTP2GO:

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import nodemailer from 'nodemailer';

async function sendEmail({ to, from, subject, message }) {
  const transporter = nodemailer.createTransport({
    host: '',
    port: 2525,
    secure: false,
    auth: {
      user: process.env.SMTP2GO_API_KEY,
      pass: '',

  try {
    const info = await transporter.sendMail({
      from: from,
      to: to,
      subject: subject,
      text: message,

    console.log('Email sent successfully:', info.messageId);
    return info.messageId;
  } catch (error) {
    console.error('Error sending email:', error);
    throw error;

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In this code, the sendEmail function accepts an object with the to, from, subject, and message properties. It uses the `nodemailer` package to create a transporter that connects to SMTP2GO's SMTP server and sends the email. To send an email from any part of your Next.js application, import the `sendEmail` function and invoke it with the appropriate email details. Here's an example usage:

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try {
  await sendEmail({
    to: '',
    from: '',
    subject: 'Hello from Next.js',
    message: 'This is a test email sent from Next.js using SMTP2GO.',
  console.log('Email sent successfully!');
} catch (error) {
  console.error('Error sending email:', error);
  // Handle error case
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By creating this helper function, you can easily integrate email-sending functionality into various parts of your Next.js application. SMTP2GO handles the actual email delivery, ensuring reliable and scalable email-sending capabilities.

Integrating the Helper Function into Next.js

Once you have developed the helper function for sending emails, the next step is to integrate it into your Next.js application.

Identifying Areas Requiring Email Functionality

Before integrating the helper function, identify the areas in your Next.js application where email functionality is required. These areas may include:

  • User registration: Sending a welcome email to new users upon successful registration.
  • Password reset: Sending an email with a password reset link to users who have forgotten their passwords.
  • Contact forms: Sending email notifications when users submit contact or inquiry forms.
  • Order confirmation: Sending order confirmation emails to customers after successful purchase.
  • Transactional emails: Sending email notifications for various events or actions within your application.

Integration of the Helper Function

To integrate the helper function into your Next.js application, follow these steps:

  1. Determine the component, page, or API route where you want to trigger the email sending functionality.
  2. Import the sendEmail function into the relevant file.
  3. Call the sendEmail function with the appropriate email details within the component, page, or API route. For example:

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import { sendEmail } from '../utils/email.js';

// Example integration in a Next.js page
export default function ContactFormPage() {
  const handleSubmit = async (event) => {

    // Process form data and prepare email details
    const emailDetails = {
      to: '',
      from: '',
      subject: 'New contact form submission',
      message: '...',

    try {
      await sendEmail(emailDetails);
      console.log('Email sent successfully!');
      // Perform any additional actions after successful email sending
    } catch (error) {
      console.error('Error sending email:', error);
      // Handle error case

  return (
{/* Form fields */}
); }
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Adjust the email details and the triggering mechanism based on your specific requirements.

Enabling Triggered Email Sending

To enable triggered email sending based on business logic, follow these steps:

1. Identify the events or conditions in your application where email notifications should be sent. For example:

  • After successful order placement, you want to send an order confirmation email to the customer.
  •  When a user requests a password reset, you want to send a password reset link to the user's registered email address.

2. Locate the relevant event handlers, listeners, or functions in your Next.js application where these conditions occur.

Implement the sendEmail function in your code. Here's an example of how it could be defined:

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async function sendEmail(recipient, subject, content) {
  // Code to send the email using your preferred email sending library or service
  // Make sure to handle any errors that may occur during the email sending process

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. Within the identified event handlers or functions, call the sendEmail function with the necessary email details. For example:

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// After a successful order placement
async function handleSuccessfulOrderPlacement(order) {
  // Code to handle the order placement logic

  // Trigger the email sending functionality
  const recipient = order.customerEmail;
  const subject = 'Order Confirmation';
  const content = 'Thank you for your order!';
  await sendEmail(recipient, subject, content);

// When a user requests a password reset
async function handlePasswordResetRequest(user) {
  // Code to handle the password reset logic

  // Trigger the email sending functionality
  const recipient =;
  const subject = 'Password Reset';
  const content = 'Click the following link to reset your password: ';
  await sendEmail(recipient, subject, content);

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Remember to handle any errors that may occur during the email sending process and provide appropriate feedback or fallback options to your users.

Deployment Considerations

When deploying your Next.js application with email-sending functionality, consider the following deployment considerations for smooth operations and reliable email delivery:

  • Understand the limitations and guidelines provided by SMTP2GO, including email sending limits, restrictions on recipient addresses, attachment sizes, and content types.
  • Monitor and manage your email sending limits by regularly tracking your sending volume, setting up notifications or alarms, and utilizing monitoring tools provided by SMTP2GO.
  • Implement rate limiting in Next.js to ensure compliance with SMTP2GO's sending limits, using techniques such as token bucket algorithms or throttling and leveraging libraries or custom logic.

Error Handling and Logging:

Effective error handling and logging mechanisms are vital for identifying and resolving issues related to email sending. Consider the following practices:

  • Identify common errors and exceptions related to email sending, such as network issues or invalid addresses, and handle them gracefully with meaningful feedback to users.
  • Integrate logging mechanisms to capture relevant information about email-sending activities, including content, recipients, timestamps, and encountered errors or exceptions.
  • Utilize logging frameworks or services to centralize and analyze logged data for debugging purposes.

Testing and Quality Assurance:

  • Perform unit tests to validate components and functions responsible for email sending, covering various scenarios and error handling.
  • Implement email delivery monitoring and reporting for actionable insights and optimization.
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Pros and Cons

Pros of Sending Emails using SMTP2GO and Next.js:

  1. Reliable email delivery: SMTP2GO provides a robust SMTP server infrastructure, ensuring high deliverability rates and reliable email sending capabilities.
  2. Scalable email infrastructure: SMTP2GO is designed to handle large email volumes, making it suitable for applications with high email sending requirements.
  3. Tracking and analytics: SMTP2GO offers comprehensive tracking and analytics features, allowing you to monitor email delivery, bounces, opens, and click-through rates.
  4. Enhanced email deliverability: SMTP2GO employs various techniques and best practices to optimize email deliverability, helping to ensure that your emails reach the recipients' inboxes.
  5. Developer-friendly integration: SMTP2GO provides developer-friendly APIs and libraries, making it easy to integrate email sending functionality into your Next.js application.

Cons of Sending Emails using SMTP2GO and Next.js:

  1. Cost implications: SMTP2GO is a paid service, and the cost can vary depending on your email sending volume and specific requirements. Consider the pricing plans and evaluate the cost-effectiveness for your application.
  2. Additional configuration and maintenance: Configuring and managing SMTP2GO integration in your Next.js application requires additional setup and ongoing maintenance compared to using built-in email functionality provided by some cloud platforms.
  3. Limited template management: SMTP2GO does not provide built-in template management features. You will need to handle email template creation and management within your application.
  4. Dependency on external service: Using SMTP2GO introduces a dependency on a third-party service. Ensure you have contingency plans in case of service interruptions or downtime.

Replacing SMTP2GO Complexities with SuprSend

You can install the SuprSend Node SDK and implement the workflow on our dashboard. Installing the SuprSend Node SDK and utilizing our intuitive dashboard allows you to streamline your workflow. With SuprSend, you can access many features, such as sending emails, managing templates, handling user profiles, and triggering workflows through API calls. Our SDK provides seamless integration, allowing you to effortlessly initialize and authenticate your SuprSend account. By leveraging SuprSend's capabilities, you can focus on delivering personalized and targeted content to your users without the hassle of managing manual code complexities.


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