curl -X POST "https://api.liddie.io/invoice/exampleslug1/cancel" \
  -H "Content-Type: application/json" \
  -d '{"confirm":true}'

// Public endpoint — no credentials required, safe from the payer's browser.
const res = await fetch('https://api.liddie.io/invoice/exampleslug1/cancel', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ confirm: true }),
});
const result = await res.json();
console.log(result.status); // "CANCELLED"

{
  "success": true,
  "status": "CANCELLED"
}