How open tracking works.
A tiny invisible image reports the open. It can't read anything — here's the whole mechanism.
When you send a tracked email, MailViewed adds a 1×1 pixel invisible image with a unique address. When your recipient opens the email and their mail app loads images, that image is fetched from our server — and that fetch is the open event: this specific email was just displayed.
What the pixel can and can't do
- It reports that the email was displayed, and when.
- It cannot read the email's text, the recipient's inbox, or anything else — it's an image, not a program.
- For Gmail readers, Google loads images through its own proxy, so we typically never even see the reader's IP address.
The pixel sits at the top of your message body, so even very long emails that Gmail clips still track correctly.
Because tracking depends on images loading, a recipient who blocks images won't register an open. Every tracker shares this limit — we just don't paper over it.
Did this answer it? If not, email support — a human replies, usually within a day.