Conversions API (Meta)

The Conversions API is Meta's server-side channel for sending events like purchases and leads straight from your server to Meta, running alongside the Meta Pixel.

The Pixel lives in the browser and the Conversions API, or CAPI, lives on your server. You run both. The Pixel catches what the browser can send, and CAPI catches what the browser drops. Together they give Meta a fuller picture of who did what after clicking your ad.

The catch is that both channels often report the same event, so you have to stop Meta from counting a sale twice. You do that with a shared event ID: the Pixel and the server both tag the purchase with the same ID, and Meta deduplicates on it. Picture one checkout worth a couple thousand rupees. The browser reports it, your server reports it, the matching ID tells Meta it was one sale, not two.

Sending events is the easy part; matching them to real people is the hard part. CAPI is only as good as the customer data you feed it, like email and phone, hashed before sending. Thin data means weak matching, and weak matching means Meta cannot credit your ads well.

The Pixel sees the browser. CAPI sees everything the browser refuses to admit.