curl --request GET \
  --url https://api.example.com/api/v1/workspaces/{workspace_id}/billing/seats/preview \
  --header 'X-API-Key: <api-key>'

{
  "currency": "<string>",
  "next_invoice_amount": 123,
  "next_invoice_date": "2023-11-07T05:31:56Z",
  "next_invoice_proration": 123,
  "next_invoice_recurring": 123,
  "prorated_today": 123,
  "seat_delta": 123
}