curl --request POST \
  --url https://app.kapso.ai/api/v1/customers \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '{
  "customer": {
    "name": "New Client",
    "external_customer_id": "CLIENT-456"
  }
}'

{
  "data": {
    "id": "customer-123abc",
    "name": "Acme Corporation",
    "external_customer_id": "CUS-12345",
    "metadata": {},
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z"
  }
}