A small piece of code embedded on a webpage or in an email that fires a signal back to an advertising or analytics platform when triggered — commonly used to track conversions, page views, or specific user actions.
Why it matters
Pixels are the mechanism that actually connects an ad platform's spend to real on-site outcomes like purchases or signups — a pixel that stops firing correctly (due to a site update, a consent-management change, or a bug) can silently break attribution and conversion tracking without any obvious symptom.
In a sentence
"The conversion pixel stopped firing after the checkout page redesign, and we didn't notice until reporting looked off a week later."
Related terms
- Often confused with: Cookie (see above).
- Synonyms: Tracking tag, conversion tag.