Conversions API (CAPI)
The Conversions API is Meta's server-to-server channel for conversion events: a second delivery route for the same events the pixel sends from the browser.
Instead of the Meta pixel firing from the visitor's browser, your server, store platform, or CRM sends events like purchases and leads directly to Meta over HTTPS, where ad blockers, Safari's ITP, and consent-blocked scripts can't interrupt them. Since April 2026, Meta's one-click CAPI sets this up without a developer.
#CAPI vs the Meta pixel
The event is the same; CAPI and the pixel are two routes it can travel, and
Meta recommends running both. Give each copy the same event_id and Events
Manager deduplicates them. Skip the shared event_id and every conversion
counts twice: the silent failure that inflates ROAS.
What actually changes in your numbers when you add CAPI, and how deduplication fails, is covered in Conversions API vs the Meta Pixel.
Related terms
Meta pixel
The Meta pixel is Meta's JavaScript snippet that reports website events (PageView, Purchase, Lead) from the visitor's browser to Meta for measurement and optimization.
Server-side tracking
Server-side tracking sends conversion and analytics events from a server you control instead of the visitor's browser: a more durable route for the same events.