Ad viewability, telemetry, and impression reconciliation

Every ad interaction passes through five distinct measurement stages from server request to conversion:

1. Ad Request: The publisher page requests an eligible advertisement for a placement.

2. Filled Request: The ad server selects a matching campaign and returns the creative payload.

3. Rendered Impression: The creative successfully draws inside the sandboxed iframe and transmits a render confirmation beacon.

4. Viewable Impression: At least 50% of the creative pixels enter the visible screen viewport for at least one continuous second.

5. Click & Conversion: The visitor clicks the ad and completes a subsequent conversion action on the destination site.

A rendered ad is not always seen. An ad rendered in a footer before the user scrolls away is rendered, but non-viewable.

AdServeKit uses the industry-standard Media Rating Council (MRC) threshold: an ad is recorded as viewable when 50% or more of its surface area remains continuously visible in the viewport for at least 1.0 second.

Publishers comparing website pageviews with ad impressions should account for:

- Ad Blockers: Extensions stop ad.js before ad requests fire.

- Lazy Loading: Slots below the fold request ads only when approached.

- No-Fill: Slots without active campaigns generate requests but no renders.

- Fast Bounces: Visitors who exit immediately prevent render confirmation beacons from completing.