Conversions API
Definition
The Conversions API is Meta's way of sending an advertiser's own conversion events, such as purchases and leads, from a server to Meta rather than from the visitor's browser. Meta's documentation presents it as a link between an advertiser's marketing data and Meta's ad systems.
It normally runs alongside the Meta pixel, not instead of it. The browser and the server can both report the same purchase, so each event carries a shared event ID that lets Meta count it once. Meta's documentation says to check that events are deduplicated and matched correctly, and a set-up that skips this double-counts: purchases appear twice and ROAS looks twice as good as it is.
The real advantage is sending things a browser never sees, such as a CRM status of 'qualified', 'viewing booked' or 'paid' after a WhatsApp conversation or a phone call. Matching relies on customer details like a hashed email or phone number, which you must have collected with consent and should send only as that consent allows. Treat promises of a guaranteed uplift with suspicion and judge it by whether reported conversions reconcile with your orders and CRM.
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