Payment Request API

Payment Request API is a browser API that standardizes the checkout flow across the web. It also expedites the payment process by capturing required payment information.

For demo on how Payment Request API works with Moltin, visit GitHub.


  • Configured products and gateway using Moltin dashboard or API.


Integration steps summary

  1. Configure products through Moltin’s API or dashboard.

  2. Configure the payment gateway through Moltin’s API or dashboard.

  3. Integrate Payment Request API with your Moltin project.

Process workflow

The client application created with the Moltin’s API calls the Payment Request API and passes to the browser cart details needed for checkout. The end user can check out using their pre-configured card option (i.e. card and shipping details that are already stored in their browser). Once validated, the data is passed back and processed by Moltin’s API and your configured gateway.

Integrate with Moltin

Use Moltin’s API to create a checkout flow. See the JavaScript SDK for more API interactions. At minimum, you’ll need:

  1. Ability to add items to a cart.

  2. Ability to check out a cart.

  3. Ability to show the Payment Request API.

  4. Ability to pay for an order using data returned from Moltin and Payment API.

Configure the checkout flow

On Moltin’s side, make sure you have the basic checkout flow configured. As part of which, you’ll need to add the ability to add items to a cart.

JavaScript SDK
async function addToCart() {
try {
// Get all products in your store
const products = await Moltin.Products.All();
const product =[0];
// Add the first product to the cart
await Moltin.Cart.AddProduct(;
// Get the cart items
this.cartItems = Moltin.Cart.Items();
} catch (e) {
// Handle errors

In the example below the quantity field defaults to 1, and as such is not provided.

Implement payment detail

Integrate the new Payment Request API directly into the Moltin checkout flow by building a new PaymentRequest object using the constructor.

JavaScript SDK
// Accept a basic debit or credit card
const paymentMethods = [{ supportedMethods: ['basic-card'] }];
// Request the customer for the name, email address
const options = { requestPayerEmail: true, requestPayerName: true };
// Build a summary of the order items from the moltin cart response
const displayItems = => {
const newItem = {};
newItem.label =;
newItem.amount = {
currency: item.meta.display_price.with_tax.value.currency,
value: item.meta.display_price.with_tax.value.formatted.substring(1),
return newItem;
// Build our PaymentRequest object
const payment = new PaymentRequest(paymentMethods, {
total: {
label: 'Total',
// Show the cart totals
amount: {
currency: this.cartItems.meta.display_price.with_tax.currency,
value: this.cartItems.meta.display_price.with_tax.formatted.substring(1),
}, options);

The first argument defines the accepted payment method, credit card.

Next, we pass in the items to display. These are cart items returned from the Moltin API. It allows us to show a breakdown of the order cost in the Payment Request UI. The optional third argument is an object specifying which, if any, additional information is required from the customer. We want to get their name and email address in order to create an order with Moltin.

Display the Payment Request UI

Call the `show()` method on the PaymentRequest object to display the UI so that the end user can provide their billing information required to finalize the transaction.

The payment and address information will then be collected from the UI and used by Moltin to create an order.

To create a successful order, Moltin will use Moltin.Cart.Checkout() call and the previously specified and enabled gateway (this example uses Stripe).

JavaScript SDK
async completeOrder() {
try {
// Show the payment capture UI
const paymentResponse = await;
// Build the moltin address payload from the PaymentRequest response
const address = {
first_name: paymentResponse.details.billingAddress.recipient.split(' ')[0],
last_name: paymentResponse.details.billingAddress.recipient.split(' ')[1],
line_1: paymentResponse.details.billingAddress.addressLine[0],
postcode: paymentResponse.details.billingAddress.postalCode,
county: paymentResponse.details.billingAddress.region,
// Checkout our cart and create an order
const order = await Moltin.Cart.Checkout({
customer: {
name: paymentResponse.payerName,
email: paymentResponse.payerEmail,
shipping_address: address,
billing_address: address,
// Pay for the order with Stripe
await Moltin.Orders.Payment(, {
gateway: 'stripe',
method: 'purchase',
first_name: paymentResponse.details.cardholderName.split(' ')[0],
last_name: paymentResponse.details.cardholderName.split(' ')[1],
number: paymentResponse.details.cardNumber,
month: paymentResponse.details.expiryMonth,
year: paymentResponse.details.expiryYear,
verification_value: paymentResponse.details.cardSecurityCode,
} catch (e) {
// Handle errors

Hide the Payment Request UI

To finish the flow and hide the UI, call the complete() method on the PaymentRequest object.

JavaScript SDK
// Complete the `PaymentRequest`
return paymentResponse.complete();