curl --request POST \
  --url http://127.0.0.1:3333/v3/billing/subscription/custom-checkout \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "email": "<string>",
  "workspaceId": "<string>",
  "returnUrl": "<string>"
}
'

{
  "checkoutUrl": "<string>"
}