Tracking Email Responses/Replies in Node.js without External Services

Question

I'm working on an email tracking feature for my Node.js application, and I want to implement email response/reply tracking without relying on any external tracking provider services. I want to keep the tracking process within my application's control. However, I'm unsure about the best approach to achieve this.

Here are my requirements:

1. Email Tracking: I need to track when a recipient opens an email and when they reply to it.
2. No External Services: I want to avoid using third-party email tracking services to maintain full control over the tracking process and user data.
3. Node.js: My application is built using Node.js, so I need a solution that is compatible with Node.js. Could someone please guide me on how to implement email response/reply tracking within my Node.js application? What libraries or techniques can I use to achieve this? Any code examples or step-by-step instructions would be greatly appreciated. Thank you!

Answer 1

There are different ways to implement email response/reply tracking in Node.js, but I’ll try to explain one possible approach using IMAP API, a daemon application that allows you to access IMAP accounts over REST. IMAP API is a spin-off project from Nodemailer, a popular module for sending emails in Node.js. You can learn more about IMAP API from this blog post.

The basic idea is to use IMAP API to send emails with predefined Message-ID headers and then receive webhook notifications for every new message in the IMAP account. You can then filter the notifications based on the Message-ID and other criteria to identify the replies to your emails.

Here are the steps you need to follow:

1. Install and configure IMAP API on your server. You can follow the installation instructions on the blog post or the [official documentation] on GitHub.

2. Create an account for IMAP API using the web interface or the REST API. You need to provide the IMAP and SMTP settings of your email provider, as well as a webhook URL where IMAP API will send notifications for new messages.

3. Use the IMAP API REST endpoint /account/:account/send to send emails from your Node.js application. You need to specify a unique Message-ID header for each email, as well as an X-Auto-Response-Suppress header to try to prevent automated replies. You also need to store the Message-ID in your database for later reference. For example, you can use the following code snippet to send an email using axios:

   const axios = require('axios');
   
   // Generate a unique Message-ID
   
   const messageId = `<${Date.now()}-${Math.random().toString(36).substr(2, 9)}@example.com>`;
   
   // Store the Message-ID in your database
   // ...
   
   // Send the email using IMAP API
   axios.post('http://localhost:3000/account/my-account/send', {
    messageId,
    headers: {
      'X-Auto-Response-Suppress': 'OOF'
    },
    from: '[email protected]',
    to: '[email protected]',
    subject: 'Hello',
    text: 'This is a test email'
   }).then(response => {
    console.log('Email sent successfully');
   }).catch(error => {
    console.error('Error sending email:', error);
   });
   

4. Receive webhook notifications from IMAP API for every new message in your IMAP account. You need to parse the notification data and check if it is a reply to one of your emails. You can use the following criteria to filter the replies:

• The message has a References or In-Reply-To header that matches one of your stored Message-IDs.

• The message has a References or In-Reply-To header that matches one of your stored Message-IDs.

• The message has a label \Inbox (for Gmail accounts) or is in the INBOX folder (for other accounts).

• The message does not have an Auto-Submitted or X-Auto-Submitted header with a value other than “no”.

• The message does not have a Precedence header with a value of “bulk”, “junk”, or “list”.

• The message does not have an X-Failed-Recipients header.

If the message passes these filters, then it is most likely a reply to one of your emails. You can then perform any action you want with the reply, such as updating your database, sending a confirmation email, triggering a workflow, etc.

For example, you can use the following code snippet to handle webhook notifications using express:

const express = require('express');
const app = express();

// Parse JSON body
app.use(express.json());

// Handle webhook notifications
app.post('/webhook', (req, res) => {
  // Get the notification data
  const { path, labels, data } = req.body;

  // Check if the message is in INBOX or has \\Inbox label
  const isInbox = path === 'INBOX' || labels.includes('\\Inbox');

  // Check if the message has a References or In-Reply-To header
  const references = data.headers.references || data.headers['in-reply-to'];
  const isReply = references && references.length > 0;

  // Check if the message has an Auto-Submitted or X-Auto-Submitted header
  const autoSubmitted = data.headers['auto-submitted'] || data.headers['x-auto-submitted'];
  const isAuto = autoSubmitted && autoSubmitted !== 'no';

  // Check if the message has a Precedence header
  const precedence = data.headers.precedence;
  const isBulk = precedence && ['bulk', 'junk', 'list'].includes(precedence.toLowerCase());

  // Check if the message has an X-Failed-Recipients header
  const failedRecipients = data.headers['x-failed-recipients'];
  const isFailed = failedRecipients && failedRecipients.length > 0;

  // If the message is a reply and not an automated or failed message, then process it
  if (isInbox && isReply && !isAuto && !isBulk && !isFailed) {
    // Get the Message-ID of the reply
    const replyId = data.headers['message-id'];

    // Get the Message-ID of the original message from the References or In-Reply-To header
    const originalId = references.split(' ').pop();

    // Check if the original Message-ID is in your database
    // ...

    // If yes, then perform any action you want with the reply
    // ...
  }

  // Send a 200 OK response
  res.sendStatus(200);
});

// Start the server
app.listen(3000, () => {
  console.log('Server listening on port 3000');
});

I hope this helps you to implement email response/reply tracking in Node.js

Answer 2

• Create a webhook handler that receives and parses the webhook payload from the source service. You can use Express and body-parser to create a simple server that listens for POST requests on a specific endpoint. For example, you can create a route like this:

  app.post("/webhook", (req, res) => {
    // Get the webhook payload from the request body
    const payload = req.body;
  
    // Do something with the payload
    console.log(payload);
  
    // Send a response to acknowledge the webhook
    res.status(200).end();
   });

• Use an email service like SendGrid or Mailgun to send an email based on the webhook data. You can use their API clients to create and send an email message with the relevant information. For example, you can use SendGrid to send an email like this:

  // Require the SendGrid client
  const sgMail = require("@sendgrid/mail");
  
  // Set your SendGrid API key
   sgMail.setApiKey(process.env.SENDGRID_API_KEY);
  
  // Create an email message
  
   const msg = {
    to: "[email protected]", // Change to your recipient
    from: "[email protected]", // Change to your verified sender
    subject: "Webhook event",
    text: `A webhook event has occurred: ${payload.event}`,
    html: `A webhook event has occurred: ${payload.event}`,
  };
  
   // Send the email message
   sgMail
    .send(msg)
    .then(() => {
      console.log("Email sent");
    })
    .catch((error) => {
      console.error(error);
  });

• Make sure your webhook handler is accessible from the internet. You can use a service like ngrok or localtunnel to expose your local server to a public URL. For example, you can use ngrok to create a tunnel like this:

  ngrok http 3000

  This will generate a URL like https://12345678.ngrok.io that you can use as your webhook endpoint.

• Register your webhook endpoint with the source service. You need to provide the URL of your webhook handler to the service that will send the webhook events. This may vary depending on the service, but usually you can find a section in their dashboard or documentation where you can configure your webhooks. For example, you can use Bearer1 to manage and monitor your webhooks from different services.