Exemplo completo

<form id="payment-form">
  <div id="card-element"></div>
  <button id="submit-btn" type="submit">Pagar</button>
</form>

app.post("/api/pay", async (req, res) => {
	const { token, amount, installments } = req.body;

	const response = await fetch("https://api-sandbox.pagou.ai/v2/transactions", {
		method: "POST",
		headers: {
			"Content-Type": "application/json",
			Authorization: `Bearer ${process.env.PAGOU_TOKEN}`,
		},
		body: JSON.stringify({
			external_ref: "order_2001",
			amount,
			currency: "BRL",
			method: "credit_card",
			token,
			installments,
			buyer: {
				name: "Ada Lovelace",
				email: "ada@example.com",
				document: {
					type: "CPF",
					number: "12345678901",
				},
			},
			products: [{ name: "Atualização de plano", price: amount, quantity: 1 }],
		}),
	});

	res.json(await response.json());
});