Runtime Q&A: CAPI & Tag Gateway
One canonical question per page, answered from server-side conversion engineering work - not a forum thread. Every fix closes with runtime verification: what to open in the platform's own diagnostics, what a pass looks like, and what a still-broken result looks like.
Questions Answered Here
Eight of the recurring problems teams hit implementing Meta Conversions API and first-party tag proxying - deduplication, attribution, exact field formatting, and the Pixel-versus-CAPI question underneath most of them.
How does Google Tag Gateway (first-party tag proxying) scope apply across subdomains, and how do I exclude specific pages?
CAPI-01Why doesn't Meta Conversions API deduplicate against my Pixel event even with a matching eventID?
CAPI-02Why do my Meta CAPI events show in Events Manager but never get attributed in Ads Manager?
CAPI-03What exact user_data formatting does Meta CAPI require for event_time and IP/user-agent to be accepted?
CAPI-04Do I still need the Facebook Pixel if I've implemented Conversions API, or can I remove it?
CAPI-05Meta's API returns 200 for my test event, so why does nothing appear in the Test Events tool?
CAPI-06What's the correct way to forward Meta Conversions API events through a server-side GTM container?
CAPI-07How do I map GA4-style item/product arrays into the Meta Conversions API purchase payload?
Not Listed Here?
If your symptom is not one of these eight, tell us the platform and what you are seeing in its own diagnostics tool, and we will tell you whether it is a known pattern or something specific to your stack.
The Rest Of The Practice
CAPI Service Overview
The four-discipline framework - install, consent-gate, dedupe, verify - applied to every platform.
Read →Audience Infrastructure
The outbound half of the same pipe, used for targeting instead of measurement.
Read →Server-Side GTM
gtm.webclat.com - the event-capture layer most CAPI implementations here extend.
Visit →