# Build a Multi-Customer App

`intent: multi-customer`

Use this path when your app accesses impact.com data on behalf of users.

### Set up OAuth 2.0

Follow the Authorization Code flow with PKCE.

* [Set Up OAuth 2.0](/rest-apis/wip-not-used-yet/authenticate/set-up-oauth-2.0.md)

### Make your first API call

Call the API with a bearer token.

Pick the base path that matches your app’s account type.

{% tabs %}
{% tab title="Brand" %}

```bash
curl -X GET "https://api.impact.com/Advertisers/{AccountSID}/Campaigns" \
  -H "Authorization: Bearer {ACCESS_TOKEN}" \
  -H "Accept: application/json"
```

{% endtab %}

{% tab title="Partner" %}

```bash
curl -X GET "https://api.impact.com/MediaPartners/{AccountSID}/Campaigns" \
  -H "Authorization: Bearer {ACCESS_TOKEN}" \
  -H "Accept: application/json"
```

{% endtab %}

{% tab title="Agency" %}

```bash
curl -X GET "https://api.impact.com/Agencies/{AccountSID}/Campaigns" \
  -H "Authorization: Bearer {ACCESS_TOKEN}" \
  -H "Accept: application/json"
```

{% endtab %}
{% endtabs %}

### Explore next step

* [Authenticate](/rest-apis/wip-not-used-yet/authenticate.md)
* [Use Webhooks](/developer-tools/webhooks.md)
* [Use Sandbox](/developer-tools/sandbox.md)


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