Seamless SDK (Payment Web)

Follow this step-by-step guide to implement and enable Yuno's Seamless Web SDK payment functionality in your application.

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Recommended SDK

We recommend using the Web Seamless SDK for a smooth integration experience. This option provides a flexible payment solution with pre-built UI components and customization options.

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Should I use Lite or Full Seamless SDK?

Use the Full Seamless SDK for automatic payment method listing and separate display of payment buttons (like PayPal). The Lite Seamless SDK gives you more control over how payment methods are displayed and organized.

Step 1: Include the library in your project

The integration guide provides three flexible methods:

1. Direct HTML script inclusion
2. Dynamic JavaScript injection
3. NPM module installation

Choose the integration method that best suits your development workflow and technical requirements. After completing the SDK integration, you can proceed with the following steps to implement the Seamless functionality.

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TypeScript Library

If you are using TypeScript, Yuno offers a library that provides access to all available methods in the Yuno Web SDK.

Step 2: Initialize SDK with the public key

Initialize the Yuno SDK in your JavaScript application by providing a valid PUBLIC_API_KEY:

const yuno = await Yuno.initialize(PUBLIC_API_KEY);

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Credentials

See the credentials page for more information: https://docs.y.uno/reference/authentication

Step 3: Create a checkout session

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If your workflow requires sending the additional_data object, it can be sent as part of the checkout session.

To initialize the payment flow, create a new checkout_session using the Create checkout session endpoint.

• First, create a customer or retrieve an existing customer ID
• Include it when creating the checkout_session

Key parameters

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onPaymentMethodSelect Event

For all APMs, including Google Pay, Apple Pay, and PayPal, onPaymentMethodSelected is triggered as soon as the customer chooses the payment method (before the payment flow begins). Define onPaymentMethodSelected in startSeamlessCheckout before mountSeamlessCheckout.

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Google Pay and Apple Pay Display

From SDK version 1.5, Google Pay and Apple Pay appear as direct buttons instead of radio buttons in the payment methods list. They are displayed separately from other payment methods.

Step 4: Start the checkout process

Use the configuration below to provide a seamless and user-friendly payment experience for your customers:

yuno.startSeamlessCheckout({
  checkoutSession: "438413b7-4921-41e4-b8f3-28a5a0141638",
  elementSelector: "#root",
  countryCode: "US",
  language: "en-US",
  showLoading: true,
  issuersFormEnable: true,
  showPaymentStatus: true,
  onLoading: (args) => console.log(args),
  renderMode: {
    type: "modal",
    elementSelector: {
      apmForm: "#form-element",
      actionForm: "#action-form-element",
    },
  },
  card: {
    type: "extends",
    styles: "",
    cardSaveEnable: false,
    texts: {},
    cardNumberPlaceholder: "Enter card number", // Optional: Custom placeholder text
    hideCardholderName: false, // Optional: Set to true to hide cardholder name field
  },
  texts: {},
  async yunoCreatePayment(oneTimeToken, tokenWithInformation) {
    await createPayment({ 
      oneTimeToken, 
      checkoutSession,
      vault_on_success: true 
    });
    yuno.continuePayment({ showPaymentStatus: true });
  },
  yunoPaymentMethodSelected(data) {
    console.log("Payment method selected:", data);
  },
  yunoPaymentResult(data) {
    console.log("Payment result:", data);
    yuno.hideLoader();
  },
  yunoError(error, data) {
    console.error("An error occurred:", error);
    yuno.hideLoader();
  },
});

When using startSeamlessCheckout, specify the callbacks to handle payments. You can also customize the checkout interface using the texts objects.

Parameters

Configure the seamless checkout with the following options:

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Customer and Merchant-Initiated Transactions

Payments can be initiated by the customer (CIT) or by the merchant (MIT). You find more information about their characteristics in Stored credentials.

The step-by-step on this page refers to a customer-initiated transaction without the recurrence option. Typically, it's used in one-time online purchases, in-store purchases, ATM withdrawals, etc.

Step 5: Mount the SDK

To present the checkout process based on the selected payment method, use the yuno.mountSeamlessCheckout() function. This step ensures the SDK is properly mounted on your chosen HTML element.

yuno.mountSeamlessCheckout({
  paymentMethodType: PAYMENT_METHOD_TYPE,
  vaultedToken: VAULTED_TOKEN,
});

See the Payment type page to view the complete list of payment method types you can use when mounting the SDK.

The vaultedToken is optional. It represents a previously enrolled payment method. If you provide the vaultedToken, the user will not be required to provide the payment information again since it was provided in a previous transaction.

After mounting, you must start the checkout flow by calling yuno.startPayment(). If you skip this call, the payment form will not open.

Step 6: Start the payment flow (Required)

Call yuno.startPayment() immediately after yuno.mountSeamlessCheckout() to open the selected payment method UI:

yuno.mountSeamlessCheckout({
  paymentMethodType: PAYMENT_METHOD_TYPE,
  vaultedToken: VAULTED_TOKEN,
});

yuno.startPayment();

Alternatively, you can trigger the start from a user action such as a button click:

const payButton = document.querySelector('#button-pay');
payButton.addEventListener('click', () => {
  yuno.startPayment();
});

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Demo App

In addition to the code examples provided, you can access the Demo App for a complete implementation of Yuno SDKs. The demo app includes working examples of all Yuno SDKs and can be cloned from the GitHub repository.

Mount external buttons

You can use the mountExternalButtons method to render Google Pay and Apple Pay buttons in custom locations within your UI. This gives you control over where these buttons are displayed.

await yuno.mountExternalButtons([
  {
    paymentMethodType: 'APPLE_PAY',
    elementSelector: '#apple-pay',
  },
  {
    paymentMethodType: 'GOOGLE_PAY',
    elementSelector: '#google-pay',
  },
]);

Parameters

Unmounting buttons

You can unmount a single external button by payment method type:

yuno.unmountExternalButton('APPLE_PAY');

Or unmount all external buttons at once:

yuno.unmountAllExternalButtons();

Enrolling payment methods in seamless flow

You can enroll payment methods (store cards for future use) directly during the seamless payment flow by setting vault_on_success: true when creating the payment in your yunoCreatePayment function.

When vault_on_success is set to true:

• The payment method will be automatically enrolled if the payment status is SUCCEEDED
• If the payment does not succeed, no vaulting will occur
• The payment response will include a vaulted_token that you can use for future transactions

Example:

async yunoCreatePayment(oneTimeToken, tokenWithInformation) {
  const paymentResponse = await createPayment({ 
    oneTimeToken, 
    checkoutSession,
    vault_on_success: true 
  });
  
  // The payment response will include vaulted_token if payment succeeded
  if (paymentResponse.vaulted_token) {
    console.log('Payment method enrolled:', paymentResponse.vaulted_token);
  }
  
  yuno.continuePayment({ showPaymentStatus: true });
}

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Vaulting Requirements

To generate and receive a vaulted_token when vault_on_success = true, the payment must reference an existing Yuno customer through customer_payer.id in the checkout session. Creating or sending the customer data inline inside the payment request does not create the customer on our side, so no vaulting will occur.

For more information about enrolling payment methods, see Enroll Payment Methods.

Stay updated

Visit the changelog for the latest SDK updates and version history.