PayPal

{
  "clientId": "Ac3..._8",
  "merchantId": null
}

// From the standalone session in step 1:
const { clientId, merchantId } = standaloneSession;

// Load the PayPal SDK with the clientId. Set the intent parameter to match the
// transaction intent and the connection's configured intent (authorize or capture).
// This example uses capture, matching the transaction and session data below:
// <script src="https://www.paypal.com/sdk/js?client-id=${clientId}&currency=USD&intent=capture"></script>
//
// When merchantId is not null, add it as the merchant-id parameter:
// <script src="https://www.paypal.com/sdk/js?client-id=${clientId}&merchant-id=${merchantId}&currency=USD&intent=capture"></script>

let defaultCompletionUrl = null;

paypal.Buttons({
  fundingSource: paypal.FUNDING.PAYPAL,
  createOrder: async function() {
    // Step 3: your server creates the transaction (needs the private key).
    const { transactionId, sessionToken } = await createTransaction();

    // Step 4: exchange the session token for the orderId and completion URL.
    const session = await fetchTransactionSession(transactionId, sessionToken);
    defaultCompletionUrl = session.default_completion_url;
    return session.session_data.orderId;
  },
  onApprove: function() {
    // After the buyer approves, navigate to the default_completion_url to
    // finalize the transaction. That URL returns an HTTP 303 redirect back to
    // your redirect_url with the transaction result appended.
    window.location.assign(defaultCompletionUrl);
  }
}).render('#paypal-button-container');

POST /transactions/:transaction_id/session?token=:session_token

{
  "session_data": {
    "intent": "CAPTURE",
    "orderId": "5O190127JK314159X",
    "clientId": "Ac3..._8",
    "currency": "USD",
    "merchantId": "9X...L",
    "fundingSource": "paypal"
  },
  "default_completion_url": "https://api.sandbox.spider.gr4vy.app/transactions/:transaction_id/approval/some-token",
  "integration_client": "web"
}