Glossary · Analytics & web
Tracking pixel
A tracking pixel is a tiny, invisible image embedded in a page or email whose load request signals to the hosting server that the content was opened, along with the viewer’s IP and client details.
The mechanism is simple: a 1x1 transparent image tag points at a URL unique to the recipient or session. Loading the page or email triggers an HTTP request for that image, and the mere act of fetching it — not any interaction with visible content — tells the server the content was viewed, when, from what IP, and with what client software. No click or explicit action is required.
On the web, pixels are a common cross-site tracking mechanism, often paired with third-party cookies to build advertising profiles. In email, they are the standard method behind "open tracking": read receipts the recipient never explicitly granted. Because loading remote images can be disabled or blocked, pixel-based tracking is inherently unreliable — but it is also silent, which is what makes it a privacy concern independent of its accuracy.
Ciphera Relay sends transactional email with no tracking pixels and no open tracking of any kind — a delivered message stays a private exchange between sender and recipient, not a telemetry event.