Question

Recently by mistake our Conversions API was firing every time we had a website visit rather than a conversion. We spend  6k a day so over the course of a few hours it was a lot of data. We caught it and fixed it. That was on Friday, today our CPL is absolutely through the roof. Could this be the affect of bad data from the mistake on conversions API?

Answer 1

Yes, absolutely—the spike in your Cost Per Lead (CPL) could very well be caused by the bad data sent through the Conversions API.

Why It Matters:

When your Conversions API fired for every page visit (instead of actual conversions), Meta’s algorithm learned the wrong behavior. It began optimizing for clicks or page views, not real leads—confusing signal quality leads to poor targeting and delivery.

Even though you fixed it, Meta likely:

- Re-entered learning phase, needing fresh conversion data.

- Lost confidence in your signal quality, slowing optimization.

- Shifted delivery toward lower-intent traffic due to false positives.

What You Should Do:

1. Let Meta re-learn—give it a few days to collect clean data.
2. Use a highest-quality event (like leads, purchases) only.
3. Exclude page view events from CAPI unless intentional.
4. Monitor event deduplication (Pixel + CAPI)—check Events Manager.
5. If things don’t normalize in 3–5 days, consider resetting the campaign or duplicating it to start fresh.