Everyone trusts the platform's auto-optimizer. Whose objective is it optimizing?

Everyone trusts the platform's auto-optimizer. Whose objective is it optimizing?

Native platforms push "automatic" or "target CPA" bidding hard. Convenient. Also a black box that conveniently spends your budget into supply where the platform's take is highest.

The tell: turn on auto-optimization and watch spend migrate toward high-volume, low-scrutiny source IDs. The CPA "target" gets hit by counting soft conversions and assist-padded attribution, while your true incremental ROAS quietly sags.

Run your own postbacks. Compare platform-reported conversions to your server-side truth. A 20-40% gap between their number and yours is common — and that gap is exactly the size of your misplaced trust.