Scout — Viewability Measurement

Scout measures whether ads were actually seen, not just served. It computes viewability and video completion rates from real VAST tracking events fired by video players and SSAI platforms.

How it works

Every VAST response from Praevis includes tracking events:

<TrackingEvents>
  <Tracking event="start">...</Tracking>
  <Tracking event="firstQuartile">...</Tracking>
  <Tracking event="midpoint">...</Tracking>
  <Tracking event="thirdQuartile">...</Tracking>
  <Tracking event="complete">...</Tracking>
</TrackingEvents>

When a video player (or SSAI platform like Broadpeak/Amagi) plays the ad, it fires these events back to Praevis. Scout aggregates them into viewability metrics.

Metrics

Dashboard

The Scout viewability card appears on the main dashboard alongside other key metrics:

• MRC Compliant (green) — viewability >= 70%
• Acceptable (yellow) — viewability >= 50%
• Low (gray) — viewability < 50%

Data sources

All events are stored in the auction_events table and aggregated by the ops-worker every 3 minutes.

SSAI compatibility

Scout works with all SSAI platforms:

• Broadpeak — fires tracking events server-side during ad stitching
• Amagi — fires tracking events during FAST channel playout
• Direct players — CTV apps and web video players fire events client-side

No SDK or client-side integration needed. Scout is purely server-side, powered by standard VAST tracking events.

Scout API

Live metrics

GET /api/metrics/live

Includes viewability_rate, completion_rate, video_starts, video_completes.

Publisher viewability

GET /api/scout/publisher/{publisher_id}

{
  "publisher_name": "Example Publisher",
  "viewability_rate": 99.9,
  "completion_rate": 98.9,
  "score": 98,
  "grade": "A+",
  "starts": 3887,
  "completes": 3845
}

Campaign viewability

GET /api/scout/campaign/{campaign_id}

Returns viewability + VCR with per-publisher breakdown.

Exchange leaderboard

GET /api/scout/leaderboard
X-API-Key: {YOUR_KEY}

Returns all publishers ranked by viewability score. Requires a valid partner, publisher, or DSP API key.

Auction verification

GET /api/scout/verify?auction_id={id}

Returns proof that a specific auction was viewable — which VAST events fired, whether midpoint was reached.

Pre-bid signal

Scout injects viewability data into bid requests so DSPs can bid higher on proven-viewable inventory:

{
  "imp": [{
    "ext": {
      "scout": {
        "publisher_viewability": 99.9,
        "publisher_vcr": 98.9,
        "publisher_score": 98,
        "publisher_grade": "A+",
        "measurement": "vast_events",
        "sample_size": 3887
      }
    }
  }]
}

Verification tag

Every VAST response includes a Scout verification node:

<AdVerifications>
  <Verification vendor="scout.praevis.com">
    <TrackingEvents>
      <Tracking event="verificationNotExecuted">
        https://rtb.praevis.com/api/scout/verify?auction_id=...
      </Tracking>
    </TrackingEvents>
  </Verification>
</AdVerifications>

Scoring

Praevis feature family