curl --request POST \
  --url https://www.dench.com/api/v1/email/campaigns/{campaignId}/recipients \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "recipients": [
    {
      "email": "ada@lovelace.dev",
      "displayName": "Ada Lovelace",
      "personalization": {
        "firstName": "Ada",
        "company": "Lovelace Labs"
      }
    }
  ]
}
'

{
  "added": 47,
  "duplicates": 2,
  "suppressed": 1,
  "invalid": 0,
  "totalRecipients": 120
}