---
type: "Glossary Term"
title: "What is CAPI (Conversions API)? | Roicool"
description: "What is CAPI? The interface that sends conversion data to ad platforms from your server or CRM: the Meta Conversions API, deduplication and matching."
url: "https://www.roicool.com/en/glossary/capi"
lang: "en"
dateModified: "2026-10-20"
resource: "https://www.roicool.com/en/glossary/capi"
alternates:
  tr: "https://www.roicool.com/sozluk/capi.md"
generated: { by: "process:roicool-cms", at: "2026-10-20T15:58:41.896Z" }
related:
  - { title: "Server-side tracking", resource: "https://www.roicool.com/en/glossary/server-side-tracking.md" }
  - { title: "Offline conversion", resource: "https://www.roicool.com/en/glossary/offline-conversion.md" }
  - { title: "Tracking in Digital Marketing", resource: "https://www.roicool.com/en/glossary/tracking.md" }
  - { title: "Server-side tracking", resource: "https://www.roicool.com/en/services/server-side-tracking.md" }
  - { title: "Glossary", resource: "https://www.roicool.com/en/glossary.md" }
---

# What is CAPI?

CAPI (Conversions API) is an interface that lets you send conversion and event data to ad platforms from the company's server or CRM instead of the browser pixel. The term is used most often for the Meta Conversions API; platforms such as LinkedIn and TikTok have similar server-side interfaces. It works alongside the pixel.

## In short

CAPI is mainly used to recover signals the pixel loses to browser restrictions and ad blockers. Its bigger value is sending outcomes that happen off the website, such as a lead marked qualified in the CRM or a closed sale, back to the ad platform. Campaign algorithms can then optimise for real business results rather than form counts. A B2B company, for example, might send Meta only the leads its sales team has accepted, so delivery shifts toward people who resemble them.

## Key points

- CAPI sends events to ad platforms from the company's server or CRM rather than the browser.
- It works alongside the pixel, and duplicate events are matched by a shared event ID.
- Hashed email, phone and click ID help match each event to a user.
- It fills in browser-blocked signals and reports off-site outcomes such as sales.
- The term usually means Meta's API; LinkedIn and TikTok offer similar interfaces.

## How does it work?

An event (a form submission, a purchase, a qualified lead in the CRM) is sent from the server to the platform. If the same event arrives from both the pixel and the server, it is deduplicated with a shared event ID. Parameters such as hashed email, phone and click ID are sent so the event can be matched to the user.

## Why it matters

It fills in signals blocked in the browser and carries outcomes that happen outside the website (sales, qualified leads) back to the ad platform, so campaigns optimize for real results rather than form counts. More detail: [What is the Meta Conversions API](https://www.roicool.com/en/blog/what-is-meta-conversions-api), setup: [server-side tracking](https://www.roicool.com/en/services/server-side-tracking).

## Related terms

- [Server-side tracking](https://www.roicool.com/en/glossary/server-side-tracking)
- [Offline conversion](https://www.roicool.com/en/glossary/offline-conversion)
- [Tracking in Digital Marketing](https://www.roicool.com/en/glossary/tracking)

## Related service

- [Server-side tracking](https://www.roicool.com/en/services/server-side-tracking)

Breadcrumb: [Home](https://www.roicool.com/en) › [Glossary](https://www.roicool.com/en/glossary) › CAPI (Conversions API)

Related pages:

- [Glossary](https://www.roicool.com/en/glossary)

Source: https://www.roicool.com/en/glossary/capi · Last updated: 2026-10-20