Email tracking relies on a tiny, invisible image being loaded when a recipient opens an email. While this is the industry standard for tracking email opens, there are some limitations that can affect tracking accuracy.
Some email clients block images by default
If a recipient's email client blocks images or requires the recipient to manually load them, an email open may not be recorded until the images are displayed.
Privacy features can affect tracking accuracy
Some email providers and privacy-focused tools preload or proxy images to protect user privacy. Examples include Apple Mail Privacy Protection, Gmail, and Yahoo. In these cases, an email may appear as opened even if the recipient has not personally viewed the email, or open information may be less precise.
Multiple recipients can affect open tracking
Unless per-recipient tracking is enabled, all recipients of the same email share a single tracking pixel. As a result, an email open can be detected, but it may not be possible to determine which specific recipient opened the email.
Multiple opens may not always represent unique views
A tracked email can be opened multiple times across different devices or email clients. Depending on how the recipient accesses the email, tracking data may not always perfectly reflect individual views.
Repeat opens may be grouped together
To improve tracking quality, repeated opens from the same source within a short period of time are counted as a single open. Additionally, opens generated through Apple Mail Privacy Protection, Gmail, and Yahoo may not always provide accurate device or location information.
Some automated activity is filtered automatically
Mailbutler automatically excludes certain types of non-human activity, including bot traffic, link preview services (such as Slack), and opens generated by the sender. Sender opens are only excluded when Mailbutler is installed in the sender's email client.
Opens cannot always be measured with complete accuracy
Because email tracking depends on external email clients and privacy settings that Mailbutler does not control, open tracking data should be considered a helpful indicator rather than an exact measurement of recipient activity.