curl --request POST \
  --url https://api.sandbox.external.bnznow.com/offset-gateway/orders \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <x-api-key>' \
  --header 'x-body-signature: <x-body-signature>' \
  --data '
{
  "emission_amount": 1,
  "emission_unit": "kgCO2",
  "callback_url": "<string>",
  "user": {
    "name": "<string>",
    "email": "jsmith@example.com",
    "tax_id": "<string>"
  }
}
'

{
  "order_id": "<string>",
  "emission_amount": 123,
  "emission_unit": "<string>",
  "user": {
    "name": "<string>",
    "email": "<string>",
    "tax_id": "<string>"
  },
  "callback_url": "<string>",
  "payment_url": "<string>",
  "created_at": "2023-11-07T05:31:56Z"
}