Example

{
    "id": 123,
    "campaign_id": 1,
    "referrer_id": 102,
    "first_name": "John",
    "email": "[email protected]",
    "source": "Referral Link",
    "ip": "62.90.15.90",
    "signed_up_at": "2024-12-27",
    "qualified_at": null,
    "unsubscribed_at": null,
    "extra_fields": [
        {
            "field": "Last Name",
            "value": "Smith"
        },
        {
            "field": "Country",
            "value": "Netherlands"
        }
    ]
}