At Mailbutler, we use the same technology that email newsletter services use by relying on a 1-pixel image in your email.
If you activate email tracking for a specific email, Mailbutler automatically includes a hidden 1-pixel image with a unique mail-ID into the outgoing mail.
Once the recipient opens your email, the recipient’s mail client or web service sends a request to our server in order to load the hidden 1-pixel image. Our servers then collect and store the mail-ID and the date/time of such request. We, in turn, pass on the date/time and mail-ID to your Mailbutler software where it is linked to the specific email and enables the Mailbutler software to display the second checkmark in the Sent folder.
Note: If the recipient has enabled image blocking in his mail program, our tracking pixel won’t be loaded. As a result, Mailbutler won’t be able to notify you whether this person has read your email or not. Furthermore, it can’t be specified who exactly opened your email. Mailbutler only shows you that somebody opened it.