MailTracker is a privacy-friendly email & PDF tracking platform for Gmail and Chrome. MailTracker is a tool that allows users to track the delivery and opening of their emails. It works by adding an invisible tracking image to the emails that are sent through the MailTracker service. When the recipient opens the email and the tracking image is loaded, MailTracker records the event and provides the user with information about the delivery and opening of the email, such as the time and location of the event. In addition to email tracking, MailTracker also offers a PDF tracking feature, which allows users to track the opening and engagement of PDF documents that are sent through the service. This can be useful for verifying that important documents have been received and reviewed by the recipient, or for tracking the effectiveness of PDF marketing materials.