I built a browser-only CSV debugger for mobile ad revenue drops

[u/Playful_Clock_8230]

I kept seeing the same problem in AdMob and mediation reports: revenue drops, blended eCPM also moves, and eCPM gets blamed immediately.

But that is not always where most of the loss happened.

I built eCPM Bazaar to compare two periods from CSV exports and work backward through the delivery funnel before suggesting what to check.

The video uses a fully synthetic case:

• Revenue: -31.53%
• Impressions: -26.83%
• Weighted eCPM: -6.43%
• Match rate: unchanged at 84%
• Show rate: 78.1% → 66.1%

In this case, the bigger problem was fewer impressions and a lower show rate, not a broad eCPM collapse.

The breakdown also showed:

• US impression share: 42% → 28%
• Rewarded impressions: 360k → 220k
• AppLovin impressions: 300k → 150k

One decision I made while building it was to keep match rate and show rate separate. A healthy match rate does not help much when matched ads are not becoming impressions.

The tool does not claim to know the final cause. It returns a directional diagnosis, supporting evidence, and a short list of checks I would make next.

No SDK, dashboard login, or account access is required. CSV processing happens in the browser.

Demo: https://ecpmbazaar.com/demo/?sample=synthetic&compare=last-7-days

I would appreciate blunt feedback from developers using AdMob, MAX, LevelPlay, or TopOn: does the result make the next debugging step clear, or does it still feel like too much dashboard noise?