Glossary · Marketing, CRM & Growth
Conversions API
Overview
What Conversions API is
Conversions API (CAPI) is a server-side tracking method that sends conversion events, such as purchases, leads, or sign-ups, directly from your own server, website backend, or CRM to an advertising platform's API rather than relying only on a browser pixel. Meta's Conversions API is the most widely referenced implementation, though Google, TikTok, Snap, and others offer equivalent server-side event APIs.
Because the data travels server-to-server, it is not blocked by browser ad blockers, cookie restrictions, or connection drops that cause client-side pixels to miss events. The industry standard is to run a browser pixel and CAPI together for the most complete picture.
How it works
Your server sends structured event payloads to the platform's endpoint, each containing the event name, timestamp, and hashed customer-matching parameters such as email or phone number. A shared event ID is passed on both the browser pixel event and the server CAPI event so the platform can recognize them as the same action and deduplicate, avoiding double-counted conversions.
Common setups include server-side Google Tag Manager, a conversions gateway, or a direct backend integration. Match quality improves as you pass more accurate hashed identifiers, and a healthy deduplication rate keeps reporting trustworthy.
Why it matters
After iOS privacy changes and the decline of third-party cookies, browser pixels alone under-report conversions, which starves optimization algorithms of the signal they need to find buyers. Adding CAPI restores lost event data, improving attribution accuracy and the performance of automated bidding.
For lead-gen and ecommerce businesses running paid social or search, CAPI is now close to essential rather than optional. It does require correct hashing of personal data and careful deduplication, so implementation should be tested rather than assumed to work.
Where we use it
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How our team puts Conversions API to work in real projects.
FAQ
Conversions API — common questions
What is the difference between the Meta Pixel and the Conversions API?
The Pixel tracks events from the browser using JavaScript, while the Conversions API sends the same events server-to-server. The Pixel is easier to install but vulnerable to ad blockers and cookie limits; CAPI is more resilient. Best practice is to run both and deduplicate them with a shared event ID.
Does the Conversions API require a shared event ID?
Yes, if you run both the Pixel and CAPI, each matching pair of events should carry the same event ID so the platform can deduplicate them. Without a matching ID, the same conversion can be counted twice, inflating your reported results.
Is the Conversions API only for Meta?
No. Meta's Conversions API is the best known, but Google (via server-side tagging), TikTok, Snap, Pinterest, and other platforms offer their own server-side event APIs. The general pattern of sending events server-to-server for better data quality applies across most major ad platforms.
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