Practical explanation:
When someone visits your website, the pixel fires in the background and records what they did — which pages they viewed, whether they filled out a form, or whether they completed a purchase. This data feeds back into your ad platform and tells you which campaigns are producing real results.
Without a pixel, you can see how many people clicked your ad, but not what happened next. That gap makes it very hard to optimise spend or prove ROI.
When to use it
Any time you're running paid ads, a pixel should be in place before the campaign goes live — not after. Setting it up retroactively means losing data from your earliest, often most informative, campaigns.
What to watch out for
Pixels load in the user's browser, which means ad blockers can prevent them from firing. This is a known limitation that affects data accuracy. Solutions like server-side tracking or Google Tag Gateway reduce this data loss — both of which Diligently implements as part of its tracking setup for paid ads clients.
Related terms: PPC, Remarketing, Retargeting, ROAS, Server-Side Tracking