curl -X POST 'https://api.goatpay.com.br/v1/payment-links/checkout' \
  -H 'X-API-Key: gp_live_SUA_CHAVE' \
  -H 'Content-Type: application/json' \
  -H 'Idempotency-Key: pedido-42-v1' \
  -d '{
    "linkId": "clx_link",
    "method": "PIX",
    "payerEmail": "cliente@loja.com",
    "externalReference": "pedido-42"
  }'

{
  "success": true,
  "message": "Checkout do link iniciado",
  "data": {
    "sessionId": "clx_session",
    "sessionToken": "uuid-token",
    "payCheckoutUrl": "https://pay.goatpay.com.br/pay/abc12/plano-pro/uuid-token",
    "paymentLinkId": "clx_link",
    "externalReference": "pedido-42"
  },
  "requestId": "req_abc"
}