Why we don't bid on a third of the requests we get

Of every 100 bid requests we receive, we let about 67 reach our DSP partners. The other 33 get filtered before we ever ask for a bid. We get questions about this from suppliers and partners. The short answer is that we think volume without quality is worse than no volume at all. The longer answer follows.

What we filter, in order of frequency

• 18% — missing or invalid OpenRTB consent strings in jurisdictions where they are required (GDPR, CCPA)
• 7% — geo-IP that does not match the device's declared country of operation
• 4% — app-ads.txt verification failure (the supply path declared by the publisher is not authorized)
• 2% — request shape that pattern-matches scraper or test traffic
• 2% — inventory in categories blocked by the active advertiser pool's brand-safety rules

These do not always add up cleanly to 33 because some requests fail two or more checks. We count the request once and tag it with the primary reason.

A specific cleanup story

In late November we onboarded a publisher with a CTV inventory mix that looked good on paper. Within 48 hours of going live they sent us 4.1 million bid requests. Almost all of them came from a small block of rotating IPs in a single ASN.

Our anomaly detection paused traffic from that source on autopilot. We reached out, walked through the logs together, and identified a CDN configuration bug on their side that was rebroadcasting impression callbacks from cached responses. Once they fixed it, the next batch was clean. We resumed traffic. Their fill rate went from looking great-and-fake to looking modest-and-real, and that is exactly what we wanted.

We could have just bid through the noise. Some of those impressions would have rendered to real viewers. Some would not. We chose not to find out the hard way, on someone else's budget.

The position

We would rather show DSP partners a real fill rate of 15% than a fake fill rate of 60%. Our integration partners get audit access to filter logs. We publish reasons aggregated weekly in the transparency report. If we filter your inventory and you disagree, we want to hear about it.

Programmatic ad tech has spent fifteen years optimizing for the wrong number. Adbustr is for people who want both sides of the auction clean. We hope that is most of you.