A tracking pixel is a tiny image used to measure opens and engagement. Learn how email tracking pixels work and how privacy changes affect them.
A tracking pixel is a tiny image embedded in an email that loads from a server when the email is opened. When the image loads, it triggers a request that records an open event and sometimes related metadata like device type.
Tracking pixels are widely used in email analytics, but they are not perfect. Image blocking and privacy protections can prevent pixel loads or cause them to load automatically, which can undercount or overcount opens.
Because of these limitations, clicks, replies, and conversions often provide a more reliable view of real engagement. Tracking pixels are still useful for directional insights, but they should not be the only metric guiding important decisions.