Glossary · Ad metrics
Fill Rate
The share of ad requests that are answered with a paying ad.
What is Fill Rate?
Fill rate is the percentage of ad-eligible opportunities that actually get filled with a paying advertisement, as opposed to going empty.
A higher fill rate means more of your available ad slots earn revenue. It depends on advertiser demand for your audience and context.
Fill Rate in context
To understand Fill Rate fully, it helps to know the concepts around it. Ad Inventory, the total ad space a publisher has available to sell. eCPM, effective cost per mille — estimated revenue per 1,000 ad impressions. Ad Impression, a single instance of an ad being served to a user. Ad Slot, a specific place where a single ad can appear.
Together these describe how ad metrics works in practice for an AI app, and where Fill Rate fits among them.
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