curl --request POST \
  --url https://sandbox-api.billingrails.com/v1/accounts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "external_id": "customer_12345",
  "type": "individual",
  "name": "Sarah Johnson",
  "email": "sarah.johnson@techstartup.com",
  "default_currency": "USD",
  "country": "US",
  "invoice_settings": {
    "number_prefix": "INV",
    "grace_period_days": 7,
    "net_term_days": 30
  },
  "preferred_locale": "en",
  "metadata": {
    "customer_segment": "enterprise",
    "signup_source": "website"
  }
}'

{
  "account": {
    "object": "account",
    "id": "acc_9KjL2mN4pQ",
    "created_at": "2025-06-04T14:22:15.123Z",
    "external_id": "customer_12345",
    "type": "individual",
    "name": "Sarah Johnson",
    "email": "sarah.johnson@techstartup.com",
    "default_currency": "USD",
    "country": "US",
    "invoice_settings": {
      "number_prefix": "INV",
      "grace_period_days": 7,
      "net_term_days": 30
    },
    "preferred_locale": "en",
    "metadata": {
      "customer_segment": "enterprise",
      "signup_source": "website"
    }
  }
}