Email Open Tracking: Build Your Own Pixel System with Gmail and Google Sheets

Have you ever wondered if your important emails are being opened? While many email marketing platforms offer open tracking, you can create your own system for personal or small-scale use with tools you likely already have: Gmail and Google Sheets.

This guide will walk you through creating a custom email open tracking system using a 1×1 pixel image. You’ll learn how to set up a simple server using Google Apps Script, integrate it with Google Sheets for data storage, and implement the tracking pixel in your Gmail messages.

Why Build Your Own Email Tracking System?

  1. Cost-effective: Use free tools you already have access to
  2. Privacy: Keep your data within your own Google ecosystem
  3. Customization: Tailor the system to your specific needs
  4. Learning opportunity: Gain hands-on experience with Google Apps Script

Step-by-Step Guide

1. Set Up Your Google Cloud Project

First, you’ll need to create a new Google Cloud project or use an existing one. This project will host your Apps Script application.

  1. Go to the Google Cloud Console
  2. Create a new project or select an existing one
  3. Enable the Google Apps Script API for your project

2. Create Your Google Apps Script

Next, you’ll write the code that will serve your tracking pixel and record open data.

  1. Open the Google Apps Script editor
  2. Create a new project
  3. Add the following code to your script:
function doGet(e) {
  const id = || Math.random().toString(36).substring(2, 15);
  const sheet = SpreadsheetApp.openById('YOUR_SPREADSHEET_ID').getActiveSheet();
  const lastRow = sheet.getLastRow() + 1;
  const date = new Date();

  sheet.getRange(lastRow, 1).setValue(id);
  sheet.getRange(lastRow, 2).setValue(date);

  const output = HtmlService.createHtmlOutput('<img src="cid:pixel" width="1" height="1">');

  return output;

Remember to replace ‘YOUR_SPREADSHEET_ID’ with the ID of the Google Sheet you’ll use for tracking.

3. Deploy Your Web App

Now it’s time to make your script accessible as a web application.

  1. In the Apps Script editor, click “Deploy” > “New Deployment”
  2. Choose “Web app” as the deployment type
  3. Set the necessary permissions and access levels
  4. Deploy your app and copy the provided URL

4. Implement the Tracking Pixel in Gmail

With your tracking pixel server set up, you can now add it to your emails.

  1. Compose a new email in Gmail
  2. Switch to the HTML view (if available) or use the “Insert link” feature
  3. Add this HTML to your email, replacing the URL and ID:
<img src="YOUR_TRACKING_PIXEL_URL?id=UNIQUE_ID" width="1" height="1" alt="">

5. Monitor Your Email Opens

Each time your email is opened, the tracking pixel will load, and the event will be recorded in your Google Sheet. You can now monitor this sheet to see when and how often your emails are being viewed.

Considerations and Next Steps

While this DIY tracking system can be useful, it’s important to consider a few factors:

  • Privacy: Always inform recipients if you’re tracking emails
  • Accuracy: Some email clients block images by default, which can affect tracking
  • Scale: This system works well for personal use but may need modifications for larger volumes

You might also want to explore additional features, such as:

  • Automated reporting
  • Integration with other Google services
  • More detailed tracking (e.g., device type, location)

By creating your own email tracking system, you’ve not only gained a useful tool but also valuable experience with Google Apps Script and web applications. Keep experimenting and refining your system to suit your needs!

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