curl --request POST \
  --url https://www.closient.com/billing/api/v1/billing/checkout \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "organization_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "amount_cents": 123,
  "success_url": "<string>",
  "cancel_url": "<string>"
}
'

{
  "checkout_url": "<string>"
}