PayPal iOS Demo App - SDK & Payment Link Integration

This repository contains a SwiftUI demo application that simulates a real-world merchant experience — including a cart and payment/checkout flow. It also demonstrates the steps to receive payments for in-app purchases through direct integration with PayPal. This can be used for both one time and recurring payments (for example: monthly subscriptions). Its primary purpose is to demonstrate two integration options to accept payments in iOS Apps through PayPal:

1. Direct SDK integration, offering seamless in-app checkout using native components.
2. Payment Links integration, which redirects users to a PayPal hosted checkout experience via universal links.

By providing practical examples for both approaches, this app helps developers choose the method that best fits their needs while simplifying implementation.

Payment Link	PayPal Native SDK
paylink_demo1.mp4	native_sdk_demo.mp4

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🚀 Version 1.1 Features

• Checkout with PayPal
• Checkout with Cards
• Checkout with Payment Links New
• Seamless PayPal checkout experience

🔧 Requirements

• Xcode 15.0+
• iOS 15.0+
• PayPal Business Account to receive payment
  • You can create an account by visiting PayPal.com
• PayPal iOS SDK (Optional if you're using Payment Links)
• Payment Links (Optional if you're using PayPal iOS SDK)

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🛠 Setup

Clone this repository:

git clone https://github.com/paypal-examples/paypal-ios-sdk-demo-app.git
cd paypal-ios-sdk-demo-app

Open the project in Xcode. Run the app on a simulator or device.

🔗+💳 Steps to create/manage Payment Links (One-Time Payment)

• Log into PayPal Business Account
  • Go to PayPal.com and sign in with your business account
  • Make sure you're logged in with a Business account (not Personal)
  • If you don’t have a business account, you’ll need to upgrade or create one by clicking on Sign up
• Go to Pay & Get Paid -> Create Payment Links and Buttons in the navigation menu
• Enter the product & payment details
  • Configure the Product Name, Description, Price & Currency
  • Optional: To let your customer decide the order amount (for example, to decide how many credits to buy), choose type as Customer set price
  • Go to Checkout tab and select if shipping address is required (It can be turned off for digital goods)
  • Go to Confirmation tab and use the universal link as Auto-return URL to redirect your customer to your app after they complete the payment
    • This is used to redirect users back to your app automatically through universal links after they complete a payment along with PDT (Payment Data Transfer)
    • This is required for order fulfillment and reconciliation. Refer to section below "How to do order fulfillment using Auto-Return URL, PDT and Webhook"
• Click Build It
• To find/view the previously created links, click on Back to saved links and buttons
• Payment Links support PayPal, Venmo, Pay Later, Card Payments and Apple Pay payment methods by default. You can update your preference by visiting settings.
• For a step-by-step walkthrough, check out the video tutorial on YouTube:
  • How to Create Payment Links and Buy Buttons
  • Configuring the Payment Links and Buttons Settings

🔗+🔄+💳 Steps to create/manage recurring payment links (Subscription)

• Log into PayPal Business Account
  • Go to PayPal.com and sign in with your business account
  • If you don’t have a business account, you’ll need to upgrade or create one by clicking on Sign up
• Go to PayPal Subscriptions
  • Click Pay & Get Paid -> Subscriptions in the navigation menu
• Go to Subscription plans tab
  • This view displays all the previously created payment links
• To create a new payment links, click Create Plan
  • Choose the product or service you want to set up subscriptions for
  • If you haven't created a product before, you'll need to create a product first by entering:
    • Product Name
    • Description
    • Product Type (Digital or Physical)
  • Set Up subscription plan
    • Choose pricing (fixed, quantity-based, tiered, etc.), billing cycle, etc.,
  • Confirm your plan details and turn it ON
• To copy the shareable payment link
  • Go to Subscription plans tab
  • Click on the action menu vertical three-dot menu and select Copy Link
  • Use this URL anywhere — in your app, websites, emails, etc.,
• Auto-Return URL for recurring payment links
  • This is used to redirect users back to your app automatically through universal links after they complete a payment
  • It can be used for improving the user experience and ensuring smooth post-payment flow
  • To setup Auto-Return URL and PDT for order fulfillment and reconciliation
    • Click on Account Settings in top-right corner of the navigation menu
    • In the left menu, click Website payments (under Products & Services)
    • Then click Update next to Website preferences
    • Select On in Auto return section and provide the URL
    • Select On in Payment data transfer section
    • Refer to section below "How to do order fulfillment using Auto-Return URL, PDT and Webhook"

🌐 Steps to setup universal links

• To support universal linking — allowing your app to automatically handle return URLs after a user completes a PayPal Payment Link — follow the steps below.

  • Host the Apple App Site Association (AASA) file

    • Create the apple-app-site-association file
      
    • To enable universal linking, create a file named apple-app-site-association (with no .json extension) and include the following content:

    {
      "applinks": {
        "details": [
          {
            "appIDs": [ "YOUR_TEAM_ID.YOUR_BUNDLE_ID" ],
            "components": [
              {
                "/": "/pay/success*",
                "comment": "Matches return URLs like /pay/success"
              }
            ]
          }
        ]
      }
    }

    • Replace YOUR_TEAM_ID with your Apple Developer Team ID.

    • Replace YOUR_BUNDLE_ID with your app's bundle identifier.

    • Host this file at the root of your domain (e.g., https://yourdomain.com/.well-known/apple-app-site-association) to allow iOS to verify your app's association with the domain.

      • Must be served with Content-Type: application/json and no redirects
      • Use a valid HTTPS certificate
• Enable Associated Domains in your app
  • Open Xcode and go to your app target -> Signing & Capabilities
  • Add a new capability: Associated Domains
  • Add the following entry:

  applinks:yourdomain.com

  • Do not include https://
• Handle the return URL in your app
  • SwiftUI Example: Use the .onOpenURL modifier to handle the return:

  @main
  struct PayPalDemoApp: App {
    var body: some Scene {
        WindowGroup {
            CheckoutFlow()
                .onOpenURL { url in
                    if url.path.contains("/pay/success") {
                        // Parse query params and handle success
                    }
                }
        }
    }
  }

  • UIKit Example:
    • In AppDelegate:

    func application(_ application: UIApplication,
          continue userActivity: NSUserActivity,
          restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
      guard userActivity.activityType == NSUserActivityTypeBrowsingWeb,
          let url = userActivity.webpageURL else { return false }
      if url.path.contains("/pay/success") {
        // Handle payment success or failure
        return true
      }
    }

    • In SceneDelegate.swift:

    func scene(_ scene: UIScene,
           continue userActivity: NSUserActivity) {
      if let url = userActivity.webpageURL {
        // Handle navigation or update state
      }
    }
    

How to do order fulfillment using Auto-Return URL, PDT and Webhook

• PDT (Payment Data Transfer) with Auto-Return URL is a combination of two PayPal features that will help you manage post-payment processes seamlessly
• These features work together to ensure that after a user makes a payment, they are automatically redirected to your app, and you receive all relevant payment information for processing/display
• It has transaction details such as currency (cc), amount (amt), transaction id (tx) and status (st)
• Implement PDT on your Server
  • PDT allows you to retrieve detailed transaction data from PayPal after the payment is made
  • Once the customer is redirected back to your Auto Return URL, you can use the transaction ID (tx) parameter in the URL to make a server-side request to PayPal
  • PayPal will then send you the transaction details via a secure HTTPS request

🔔 Steps to receive payment notification through Webhooks

• Using PayPal Webhooks allows your application to be automatically notified when specific events occur in your PayPal account—like a successful payment, subscription renewal, or refund
• It can be used by Merchants for real-time backend updates
• For more details on how to integrate with webhooks - click here

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📂 Project Structure

• Where to find key logic
  If you are just interested in code to implement server side and SDK API calls, you can skip to CardPaymentViewModel or PayPalViewModel
• CheckoutFlow
  SwiftUI view that is the entry point for the checkout process. It sets up the overall navigation structure using a NavigationStack, so users can move from cart checkout and finally OrderCompletion
• CheckoutCoordinator (Navigation and Flow Manager)
  Handles navigation logic and handles loading and error states of flows that do not have a dedicated SwiftUI view (e.g., PayPal Web Checkout)
• CartView
  Displays items in the cart and total amount
  Buttons to initiate Card or PayPalWeb checkout
  Tapping either calls into a CheckoutCoordinator that starts the respective flow
• Card Checkout
  This uses a SwiftUI screen called CardCheckoutView which references a CardPaymentViewModel
  The view model handles network calls for creating order, approving the card and final capture
  When complete, the user is navigated to OrderCompleteView
• PayPal Web Checkout
  No dedicated SwiftUI screen - once triggered, it opens a web flow Because there is no dedicated PayPal view, we handle loading and errors in a CheckoutCoordinator
  If the user completes the PayPal flow, we capture the order and show OrderCompleteView
• Payment Links (New)
  Opens a universal link or URL that redirects to the hosted checkout. After completion, app is notified via webhook callback