curl --request GET \
  --url https://api.withflex.com/v1/customers/{id} \
  --header 'Authorization: Bearer <token>'

{
  "customer": {
    "customer_id": "fcus_01HACM7FZ1084XB1GB6053VM0D",
    "first_name": "John",
    "last_name": "Doe",
    "email": "joh.doe@example.com",
    "phone": "+15555555555",
    "employer": "Flex",
    "shipping": {
      "shipping_address_id": "obj_01EXAMPLE00000000000000000",
      "line1": "123 Main St",
      "line2": "Suite 100",
      "city": "San Francisco",
      "state": "CA",
      "postal_code": "94107",
      "country": "US"
    },
    "metadata": {},
    "created_at": "2024-01-01T00:00:00Z",
    "test_mode": false
  }
}