paypal-integration

# PayPal Integration Master PayPal payment integration including Express Checkout, IPN handling, recurring billing, and refund workflows. ## When to Use This Skill - Integrating PayPal as a payment option - Implementing express checkout flows - Setting up recurring billing with PayPal - Processing refunds and payment disputes - Handling PayPal webhooks (IPN) - Supporting international payments - Implementing PayPal subscriptions ## Core Concepts ### 1. Payment Products **PayPal Checkout** - One-time payments - Express checkout experience - Guest and PayPal account payments **PayPal Subscriptions** - Recurring billing - Subscription plans - Automatic renewals **PayPal Payouts** - Send money to multiple recipients - Marketplace and platform payments ### 2. Integration Methods **Client-Side (JavaScript SDK)** - Smart Payment Buttons - Hosted payment flow - Minimal backend code **Server-Side (REST API)** - Full control over payment flow - Custom checkout UI - Advanced features ### 3. IPN (Instant Payment Notification) - Webhook-like payment notifications - Asynchronous payment updates - Verification required ## Quick Start ```javascript // Frontend - PayPal Smart Buttons <div id="paypal-button-container"></div> <script src="https://www.paypal.com/sdk/js?client-id=YOUR_CLIENT_ID&currency=USD"></script> <script> paypal.Buttons({ createOrder: function(data, actions) { return actions.order.create({ purchase_units: [{ amount: { value: '25.00' } }] }); }, onApprove: function(data, actions) { return actions.order.capture().then(function(details) { // Payment successful console.log('Transaction completed by ' + details.payer.name.given_name); // Send to backend for verification fetch('/api/paypal/capture', { method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({orderID: data.orderID}) }); }); } }).render('#paypal-button-container'); </script> ``` ```python # Backend - Verify and capture order from paypalrestsdk import Payment import paypalrestsdk paypalrestsdk.configure({ "mode": "sandbox", # or "live" "client_id": "YOUR_CLIENT_ID", "client_secret": "YOUR_CLIENT_SECRET" }) def capture_paypal_order(order_id): """Capture a PayPal order.""" payment = Payment.find(order_id) if payment.execute({"payer_id": payment.payer.payer_info.payer_id}): # Payment successful return { 'status': 'success', 'transaction_id': payment.id, 'amount': payment.transactions[0].amount.total } else: # Payment failed return { 'status': 'failed', 'error': payment.error } ``` ## Detailed patterns and worked examples Detailed pattern documentation lives in `references/details.md`. Read that file when the navigation tier above is insufficient. ## Testing ```python # Use sandbox credentials SANDBOX_CLIENT_ID = "..." SANDBOX_SECRET = "..." # Test accounts # Create test buyer and seller accounts at developer.paypal.com def test_payment_flow(): """Test complete payment flow.""" client = PayPalClient(SANDBOX_CLIENT_ID, SANDBOX_SECRET, mode='sandbox') # Create order order = client.create_order(10.00) assert 'id' in order # Get approval URL approval_url = next((link['href'] for link in order['links'] if link['rel'] == 'approve'), None) assert approval_url is not None # After approval (manual step with test account) # Capture order # captured = client.capture_order(order['id']) # assert captured['status'] == 'COMPLETED' ```