curl --request POST \
  --url https://staging.terminal3.io/v1/sub_client \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'x-api-token: <x-api-token>' \
  --data '
{
  "name": "<string>",
  "address_1": "<string>",
  "address_2": "<string>",
  "country": "<string>",
  "province": "<string>",
  "city": "<string>",
  "timezone": "<string>",
  "domain": "<string>",
  "subdomain": "<string>"
}
'

{
  "data": {
    "client_id": 123,
    "name": "<string>",
    "domain": "<string>",
    "timezone": "<string>",
    "address_1": "<string>",
    "address_2": "<string>",
    "country": "<string>",
    "province": "<string>",
    "city": "<string>",
    "subdomain": "<string>",
    "from_email_address": "<string>",
    "esp_token": "<string>",
    "recaptcha_key": "<string>",
    "recaptcha_threshold": 123,
    "recaptcha_enabled": true,
    "created_at": "<string>",
    "privacy_link": "<string>"
  }
}