Instead of depending only on the Pixel in a visitor's browser, CAPI transmits events from your server, a server-side tag manager, or a partner integration such as Shopify or a CRM. That makes measurement more resilient to ad blockers, browser restrictions, and connection issues, and lets you send events that happen offline — like a lead becoming a customer.
When the Pixel and CAPI send the same event, a shared event ID lets Meta deduplicate them so conversions aren't counted twice. Sending rich customer information — hashed email and phone, plus click IDs — improves Event Match Quality, which helps Meta attribute conversions and optimize delivery.
Example
When a lead from a Facebook ad later signs a contract, the company's CRM sends a Purchase event with the contract value to Meta through the Conversions API.
How Sloss Digital uses it
CAPI is standard on every Meta account we manage — deduplicated with the Pixel, enriched with customer data, and connected to the CRM so Meta optimizes for real revenue.