> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tryprofound.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Get started with Conversions API (CAPI)

> What the Profound Pixel Conversions API is, when to use it, and how to authenticate

The Conversions API (CAPI) is the server-side channel of [Profound Pixel](https://docs.tryprofound.com/pixel/overview.md). Your backend posts a conversion event straight to Profound, so nothing runs in the visitor's browser: ad blockers and privacy browsers can't drop the event, and an order confirmed hours after the visit is still recorded.

The API accepts the same [events](https://docs.tryprofound.com/pixel/events.md) as the browser pixel and records them in the same place. Only the transport differs.

## When to use it

Use the Conversions API when the conversion is confirmed on your server: a payment webhook, an offline or phone order, a subscription renewal.

To improve conversion coverage, we recommend using the [browser pixel](https://docs.tryprofound.com/pixel/overview.md) and sending the same conversions from your server. They fail in different places: the browser pixel records the visits and intent your server never sees, and the server records the orders an ad blocker, a closed tab, or a privacy browser would have dropped. Together they cover far more than either alone.

> [!TIP]
>
> Send the same order ID as `dedup_key` on both events so Profound can match the pair. See [Deduplication](https://docs.tryprofound.com/pixel-conversions-api/post-events.md#deduplication).

## Before you start

* **Have your pixel ID.** Each event names the pixel it belongs to. The [installation guide](https://docs.tryprofound.com/pixel/install.md#step-1) shows how to generate one.
* **To credit conversions to ads, install the browser pixel.** The values that credit a conversion to an ad come from the cookies the browser pixel writes. Without them, Profound records the conversion but can't credit it to an ad. See [Attribution](https://docs.tryprofound.com/pixel-conversions-api/post-events.md#attribution).

## Get a CAPI key

> [!NOTE]
>
> CAPI has its own host and key. The REST API key described in [Authentication](https://docs.tryprofound.com/rest-api/authentication.md) doesn't work here.

**1. Generate a key**

In the Profound platform, open **Ads** in the left navigation, select **Conversions**, then under **Conversions API**, select **Generate CAPI key**.

Generating a key requires pixel configuration permissions. If you don't see the button, ask someone with an [Admin or Editor role](https://docs.tryprofound.com/platform-config/people/roles-and-permissions) to generate one.

**2. Copy the key**

The key starts with `pfck_`. Profound shows it once, at creation, so copy it right away.

**3. Store it in a secure place**

Treat the key as a secret. It authenticates your whole organization and can write to any pixel your organization owns.

An organization can have up to 10 live keys. Revoked keys don't count toward the limit.