How email opens are tracked

Overview

Learn how email opens are tracked in Ortto and what factors can influence open tracking accuracy. Understanding how opens are recorded helps you better interpret email engagement and performance metrics.

How email opens are tracked

To track email opens, our system includes a tiny, invisible 1x1 pixel image in each email you send (if open tracking is enabled). When a contact opens the email and allows images to load, this image is retrieved from our servers, registering the open.

If images aren’t loaded, an open may still be recorded if the contact clicks a link in the email, provided click tracking is enabled. Both open and click tracking are turned on by default for new emails.

Example of an email with open & click tracking enabled.

Learn more about Email campaign setup.

Why opens may not be tracked

There are several reasons why an open might not be recorded:

Images are blocked by the email client – Some email providers disable image loading by default, preventing the tracking pixel from being retrieved.
Example of Outlook blocking images by default.
Open tracking is disabled – If open tracking is turned off in your email settings, opens will not be recorded.
Privacy features and extensions – Some email clients and browser extensions block tracking pixels, making opens impossible to detect.
Email is viewed in plain text – If a recipient’s email client allows viewing the email in plain text mode instead of HTML, the tracking pixel will not load.
The email is only previewed – Some email clients show a preview of the email without loading images, which does not trigger an open.

Why false opens may be recorded

In some cases, an open may be recorded even if the recipient hasn’t actually viewed the email. Here are a few reasons why this can happen:

Email security filters preloading images – Some security tools and spam filters scan incoming emails by preloading images, which can trigger the tracking pixel before the recipient opens the email.
Apple Mail Privacy Protection (MPP) – If the recipient uses Apple Mail with MPP enabled, Apple preloads all images (including tracking pixels) through proxy servers, making every email appear as opened, even if the recipient never views it. Learn more about Apple Mail Privacy Protection (MPP).
Email forwarding – If an email is forwarded, the tracking pixel may load when the next recipient opens the email, causing an open to be recorded under the original recipient.
Third-party extensions or apps – Some browser extensions and email management tools may trigger image loading when scanning or organizing emails, leading to false opens.

Apple Mail Privacy Protection (MPP)

Opens generated by Apple's MPP service are currently included in your report totals. However, when an open appears highly suspicious and likely originated from this service, we include an attribute in the Opened email activity named Possible machine open.

Example of an activity with the Possible machine open attribute.

This allows you to use the Possible machine open attribute to filter out possible machine opens when creating reports or filters.

Example of a report that filters out possible machine opens.

TIP: This attribute is only included when an open likely originated from this service, otherwise, it won't be present. To filter those out, use the condition has no value instead of is false, as shown in the GIF above.

Identifying opens from other providers is more challenging at the moment. However, we are actively working on improving our detection methods and will look to include additional providers as soon as we can ensure reliable identification.