Ad Slots

An Ad Slot in Bidkernel maps to a physical space on your webpage where an ad will render.

Defining Ad Slots Link to section

You define slots on a Property. For each slot, you provide:

• Selector: A CSS query selector that locates the ad containers on your page (e.g., .ad-slot).
• Slot name: An internal name for the slot, unique per property, using lowercase letters and underscores only (e.g., leaderboard).

Sizes are not configured in the dashboard. By default, the SDK uses the element's rendered dimensions. To request specific or responsive sizes, pass sizes and sizeMappings to window.<alias>.defineSlot() in your page code.

Viewability and Lazy Loading Link to section

The Bidkernel SDK requests bids up front (debounced), but holds rendering until the slot is at least 50% in the viewport and the page is visible.

The 50% + 1s Threshold Link to section

Bidkernel implements the standard IAB (Interactive Advertising Bureau) viewability threshold Source: MRC Viewability Guidelines View Citation → by default. The ad renders when the slot first reaches 50% in view. The viewable event is tracked once 50% of the ad's pixels stay in the viewport for at least 1 continuous second (2 seconds for video).

Auto-Refresh Link to section

A property-level refresh interval controls auto-refresh (set it to 0 to disable). Individual slots can override it — including disabling refresh — by passing the refreshInterval option to defineSlot() (0 = disabled). The refresh timer keeps running while the tab is hidden or the ad is out of view, but a refreshed ad is not rendered until the slot is viewable again.