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How Email Open Tracking Works

By Mike Donnelly on Mar 20, 2017 6:15:35 PM

How Email Open Tracking Works

Marketing automation systems; Marketo, Constant Contact, Mail Chimp, Eloqua, Act-On, Hubspot, etc. have been using email open tracking for years as a way to measure success of their email campaigns. In this post, we'll review how these technologies work and how they don't. 

Several companies have brought this same technology to sales professionals. I'm a huge fan of Yesware, Boomerang and Hubspot Sales (my favorite). If you are in sales and haven't heard of these, you should definitely check them out. That said, you need to be aware of the pitfalls of using 'email opens' as a way of figuring out whether prospective or existing customers are truly engaging in your email communications. 


To track an email, the software inserts a transparent pixel (think of this as a small picture you can't see) in your email. Once you check a box that says "track my email" and your recipient opens your email, the pixel (picture) is downloaded from a remote server which notifies you that the email was opened. Sounds great, doesn't it?

Not so fast….Based on your audience's email platform, interface and settings, it can have adverse effects. Below is a quick synopsis of how it works.

Microsoft Outlook — By default, images aren't downloaded due to security concerns (ever seen the below?). It's up to the Outlook user to click the 'download pictures' button in order to receive a notification that the email was read.

Outlook Image

Gmail — If your recipient has Gmail as their backend email provider, Google used to automatically download the pixel (picture) as soon as the email was delivered to a Google server versus read by the intended recipient, but that is no longer the case — BIG WIN for sales and marketing professionals using an email open tracking feature.

Mobile — Mobile email applications download the pixel by default as soon as the user opens your email.

Still sounds great doesn't it? It's certainly a start, however using this as your only way to understand your audience's behavior can trick you.

In my next post, we'll put you in your audience's shoes to show you the pitfalls.

Mike Donnelly

Written by Mike Donnelly

Founder and CEO - Seventh Sense