Meta Conversions API (CAPI)
What is Meta Conversions API (CAPI)?
The Meta Conversions API (CAPI) is the connection that sends events — an order, an enquiry, a payment — from your own server straight to Meta, instead of leaving it all to the browser pixel. It runs beside the pixel: the same event goes twice with a shared identifier and Meta counts it once. Reporting survives blocked scripts, but consent still decides.
Example
An online shop records 90 orders for the month in its own system. The ad report shows 61. The gap is not imaginary: some browsers block scripts, some people open the site inside an app, and some events simply never fire.
Once orders are also sent from the server, 84 of those same 90 are reported. The number of orders in the shop has not changed; what changed is what the ad system can see, and therefore what it learns from. A campaign that looked like a loss at 61 orders reads differently at 84.
Why it matters for a business
Browser-only tracking keeps getting less reliable, and an ad system optimises on whatever reaches it. Sending from the server is steadier, because it does not depend on blockers or browser settings. The same idea sits behind server-side tagging on the Google side: the event leaves your infrastructure rather than the visitor’s device.
The legal part does not change. CAPI processes personal data — email and phone are hashed before they are sent, and they remain personal data. If someone declined tracking in the banner, no event goes out on either channel. Server-side sending is not a way around consent, and the privacy policy has to say what is being sent. The connection itself behaves like any other API: an access token, and a version that eventually ages out.
What to ask
- Do both channels send a shared event identifier, so nothing is counted twice?
- How is the connection built — a platform integration, a plugin, or code of our own?
- Does the server-side path respect the choice made in the cookie banner?
- What match quality does Events Manager show, and what would raise it?
- Who maintains the connection when Meta moves to a new API version?
We set CAPI up alongside the pixel as part of Facebook and Instagram ads, once the site events have been checked one by one.