Add a hosted checkout to your mobile app

With recent developments in legislation around the App Store, you can link users in the United States to an external checkout for purchases in iOS apps.

You can use hosted checkouts to let users securely make purchases outside your app — no hosting required. Customers tap a button in your app to open a checkout that's fully hosted by Paddle, then they're redirected to your app when they complete their purchase.

What are we building?

In this tutorial, we'll use hosted checkouts in Paddle to build an external purchase flow for in-app purchases in iOS apps.

We'll walk through handling fulfillment using the RevenueCat x Paddle integration or webhooks.

What's not covered

This tutorial doesn't cover:

• Handling authentication
  We assume you already have a way to identify your users, like Firebase or Sign in with Apple.
• Native in-app purchases
  We'll launch Paddle Checkout in Safari then redirect users back to your app. Like the App Store, Paddle Checkout supports Apple Pay with no additional setup, plus other popular payment options.
• Subscription lifecycle management
  You can use Paddle to handle all parts of the subscription lifecycle, including updating payment methods and canceling subscriptions using the prebuilt customer portal. We cover that elsewhere in our docs.

Before you begin

Sign up for Paddle

You'll need a Paddle account to get started. You can sign up for two kinds of account:

• Sandbox — for testing and evaluation
• Live — for selling to customers

For this tutorial, we recommend signing up for a sandbox account. You can transition to a live account later when you've built your integration and you're ready to start selling. If you sign up for a live account, you'll need to:

• Complete account verification
  We'll ask you for some information to make sure that we can work together.
• Request hosted checkout access
  You should contact support to check you're eligible to use hosted checkouts.

Prep your iOS development environment

As part of our tutorial, we're going to update our app to include a link to a hosted checkout for purchases. You'll need:

• Some knowledge of iOS development, access to your iOS project, and Xcode on macOS.
• A correctly configured URL scheme so you can redirect users back to your app.

You don't need to make changes to your iOS app to create a hosted checkout in Paddle, so you can come back to this later if you're working with a developer.

Overview

Add a hosted checkout to your app to link out for in-app purchases in five steps:

1. Map your product catalog
   Create products and prices in Paddle that match your in-app purchase options.
2. Create a hosted checkout
   Create a hosted checkout in the Paddle dashboard, including where to redirect customers to after purchase.
3. Add a checkout button to your app
   Create a button that opens the hosted checkout URL when tapped.
4. Handle fulfillment and provisioning
   Use RevenueCat or process webhooks to fulfill purchases after a customer completes a checkout.
5. Take a test payment
   Make a test purchase to make sure your purchase flow works correctly.

Map your product catalog

Before we add a hosted checkout to our app, we need to set up our product catalog in Paddle to match the in-app purchases we offer.

Model your pricing

A complete product in Paddle is made up of two parts:

• A product entity that describes the item, like its name, description, and an image.
• At least one related price entity that describes how much and how often a product is billed.

You can create as many prices for a product as you want to describe all the ways they're billed.

In this example, we'll create a single product and single price for a one-time item called Lifetime Access.

Create products and prices

You can create products and prices using the Paddle dashboard or the API.

Create a hosted checkout

Next, create a hosted checkout. A hosted checkout is a link that users can use to make a purchase. It's unique to your account.

You can create multiple hosted checkouts if you have different apps or want to create links that redirect to different places in your app.

When creating a hosted checkout, you can set default prices. If you don't pass prices or a transaction to the checkout directly, the default prices are used instead.

Add a checkout button to your app

Now, update your iOS app to add a button that:

1. Checks to see if in-app purchases are allowed on the device.
2. Checks to see if a user already purchased the item.
3. Constructs a URL using your hosted checkout launch URL, and a price_id query parameter with the price ID you copied previously as the value.

Here's an example using SwiftUI:

import SwiftUI
import StoreKit // required for checking device payment capabilities using SKPaymentQueue

struct PurchaseView: View {
    let checkoutBaseURL = "https://pay.paddle.io/checkout/hsc_01jt8s46kx4nv91002z7vy4ecj_1as3scas9cascascasasx23dsa3asd2a" // replace with your checkout launch URL
    let priceId = "pri_01h1vjg3sqjj1y9tvazkdqe5vt" // replace with a price ID or dynamically set it

    var body: some View {
        VStack {
            // Check if the device can make payments
            if SKPaymentQueue.canMakePayments() {
                // Create a purchase button with styling
                Button("Buy now") {
                    openCheckout()
                }
                .padding()
                .background(Color.blue)
                .foregroundColor(.white)
                .cornerRadius(10)
            } else {
                // Fallback text when purchases aren't available
                Text("Purchases not available on this device.")
                    .foregroundColor(.secondary)
            }
        }
        .padding()
    }

    // Function to construct and open the checkout URL
    func openCheckout() {
        // Create URL with price_id parameter
        let checkoutURL = "\(checkoutBaseURL)?price_id=\(priceId)"
        if let url = URL(string: checkoutURL) {
            // Open URL in the default browser
            UIApplication.shared.open(url)
        }
    }
}

Prefill information Recommended

To make for a more seamless user experience, you can use URL parameters to pass additional information to the hosted checkout.

In this updated example, we pass customer details and a unique identifier for the customer in RevenueCat.

import SwiftUI
import StoreKit // required for checking device payment capabilities using SKPaymentQueue

struct PurchaseView: View {
    let checkoutBaseURL = "https://pay.paddle.io/checkout/hsc_01jt8s46kx4nv91002z7vy4ecj_1as3scas9cascascasasx23dsa3asd2a" // replace with your checkout launch URL
    let priceId = "pri_01h1vjg3sqjj1y9tvazkdqe5vt" // replace with a price ID or dynamically set it

    // Additional information
    // In a real app, this would come from your user authentication platform
    let appUserId = "85886aac-eef6-41df-8133-743cbb1daa4b"
    let userEmail = "sam@example.com"
    let countryCode = "US"
    let postalCode = "10021"

    var body: some View {
        VStack {
            // Check if the device can make payments
            if SKPaymentQueue.canMakePayments() {
                // Create a purchase button with styling
                Button("Buy now") {
                    openCheckout()
                }
                .padding()
                .background(Color.blue)
                .foregroundColor(.white)
                .cornerRadius(10)
            } else {
                // Fallback text when purchases aren't available
                Text("Purchases not available")
                    .foregroundColor(.secondary)
            }
        }
        .padding()
    }

    // Function to construct and open the checkout URL with customer data
    func openCheckout() {
        // Create URL components for building a URL with query parameters
        var urlComponents = URLComponents(string: checkoutBaseURL)!

        // Add the price ID and customer information as query parameters
        urlComponents.queryItems = [
            URLQueryItem(name: "price_id", value: priceId),
            URLQueryItem(name: "app_user_id", value: appUserId),
            URLQueryItem(name: "user_email", value: userEmail),
            URLQueryItem(name: "country_code", value: countryCode),
            URLQueryItem(name: "postal_code", value: postalCode)
        ]

        // Open the checkout URL if it's valid
        if let url = urlComponents.url {
            UIApplication.shared.open(url)
        }
    }
}

Handle fulfillment and provisioning

When a customer completes a purchase, they'll be redirected back to your app. At this point, you need to handle fulfillment and unlock the features they bought.

app.post("/paddle/webhooks", express.raw({ type: 'application/json' }), async (req, res) => {
  try {
    // You can verify the webhook signature here
    // We don't cover this in the tutorial but it's best practice to do so
    // https://developer.paddle.com/webhooks/signature-verification

    const payload = JSON.parse(req.body.toString());
    const { data, event_type } = payload;
    const occurredAt = payload.occurred_at;

    // Listen for vital events from Paddle
    switch (event_type) {
      // 1. Record transactions in the database

      // Handle a new transaction
      // You can create a Transaction database to store records and associate them to a user
      case 'transaction.created':
        // Find the user associated with this transaction
        const userForTransaction = await User.findOne({ where: { paddleCustomerId: data.customer_id } });

        if (userForTransaction) {
          await Transaction.create({
            transactionId: data.id,
            userId: userForTransaction.id,
            subscriptionId: data.subscription_id,
            status: data.status,
            amount: data.amount,
            currencyCode: data.currency_code,
            occurredAt: occurredAt
          });
        }
        break;

      // Handle a completed transaction
      // If you have a Transaction database, you can update the transaction record
      case 'transaction.completed':

        // Find the transaction by its ID
        const completedTransaction = await Transaction.findOne({
          where: { transactionId: data.id }
        });

        if (completedTransaction) {
          await completedTransaction.update({
            status: data.status,
            subscriptionId: data.subscription_id,
            invoiceId: data.invoice_id,
            invoiceNumber: data.invoice_number,
            billedAt: data.billed_at,
            updatedAt: data.updated_at
          });
        }
        break;
    }

    res.json({ received: true });
  } catch (error) {
    console.error('Error processing webhook:', error);
    return res.status(500).json({ error: error.message });
  }
});

app.post("/paddle/webhooks", express.raw({ type: 'application/json' }), async (req, res) => {
  try {
    // You can verify the webhook signature here
    // We don't cover this in the tutorial but it's best practice to do so
    // https://developer.paddle.com/webhooks/signature-verification

    const payload = JSON.parse(req.body.toString());
    const { data, event_type } = payload;
    const occurredAt = payload.occurred_at;

    // Listen for vital events from Paddle
    switch (event_type) {
      // 1. Record transactions in the database

      // Handle a new transaction
      // You can create a Transaction database to store records and associate them to a user
      case 'transaction.created':
        // Find the user associated with this transaction
        const userForTransaction = await User.findOne({ where: { paddleCustomerId: data.customer_id } });

        if (userForTransaction) {
          await Transaction.create({
            transactionId: data.id,
            userId: userForTransaction.id,
            subscriptionId: data.subscription_id,
            status: data.status,
            amount: data.amount,
            currencyCode: data.currency_code,
            occurredAt: occurredAt
          });
        }
        break;

      // Handle a completed transaction
      // If you have a Transaction database, you can update the transaction record
      case 'transaction.completed':

        // Find the transaction by its ID
        const completedTransaction = await Transaction.findOne({
          where: { transactionId: data.id }
        });

        if (completedTransaction) {
          await completedTransaction.update({
            status: data.status,
            subscriptionId: data.subscription_id,
            invoiceId: data.invoice_id,
            invoiceNumber: data.invoice_number,
            billedAt: data.billed_at,
            updatedAt: data.updated_at
          });

          // 2. Provision access to your app
          // Fetch the user associated with this transaction
          const user = await User.findOne({ where: { id: completedTransaction.userId } });

          if (user) {
            // Fetch the items from the transaction
            const purchasedItems = data.items || [];

            // Add what access the user has based on the items they purchased
            // For this example, we're using access permissions and storing them in the user model on an accessPermissions field
            // We also map the Paddle product IDs to the access permissions
            // In a real app, you could use a database table for this mapping

            // Get existing permissions to see if any first
            const accessPermissions = user.accessPermissions ? JSON.parse(user.accessPermissions) : {};

            // Map product IDs to access permissions
            // We add an additional product as an example of how you can handle multiple
            const productToPermission = {
              'pro_01h1vjes1y163xfj1rh1tkfb65': 'lifetimeAccess',
              'pro_01gsz97mq9pa4fkyy0wqenepkz': 'temporaryAccess'
            }

            purchasedItems.forEach(({ price }) => {
              const permissionKey = productToPermission[price.product_id];
              if (permissionKey) accessPermissions[permissionKey] = true;
            });

            // Update the user with their new access permissions
            await user.update({
              accessPermissions: JSON.stringify(accessPermissions),
            });
          }
        }
        break;
    }

    res.json({ received: true });
  } catch (error) {
    console.error('Error processing webhook:', error);
    return res.status(500).json({ error: error.message });
  }
});

Test the complete flow

We're now ready to test the complete purchase flow end-to-end! If you're using a sandbox account, you can take a test payment using our test card details:

Email address

An email address you own

Country

Any valid country supported by Paddle

ZIP code (if required)

Any valid ZIP or postal code

Card number

4242 4242 4242 4242

Name on card

Any name

Expiration date

Any valid date in the future.

Security code

100

Next steps

That's it. Now you've built a purchase workflow that links out to Paddle Checkout, you might like to hook into other features of the Paddle platform.

Learn more about Paddle

When you use Paddle, we take care of payments, tax, subscriptions, and metrics with one unified platform. Customers can self-serve with the portal, and Paddle handles any order inquiries for you.

Build a web checkout

Our tutorial uses a hosted checkout to build a payment workflow. You can also Paddle.js to build pricing pages and signup flows on the web, then redirect people to your app.

Build advanced subscription functionality

Paddle Billing is designed for subscriptions as well as one-time items. You can use Paddle to build workflows to pause and resume subscriptions, flexibly change billing dates, and offer trials.