Tutorial: Integrate a Public API

spark query "PayPal checkout API integration Node.js" \
  --tag library:paypal-sdk \
  --tag framework:express \
  --pretty

Session: def456

Recommendations for: "PayPal checkout API integration Node.js"
Tags: library:paypal-sdk, framework:express

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[0] PayPal Checkout REST API v2 with Express
    Confidence: 91%  |  Validations: 68  |  Source: community
    ──────────────────────────────────────────────
    Use the PayPal REST API v2 (not the deprecated v1 or legacy NVP/SOAP).
    Direct HTTP calls with @paypal/checkout-server-sdk or plain fetch.
    Two-step flow: create order, then capture payment.

[1] PayPal Smart Buttons + server-side capture
    Confidence: 87%  |  Validations: 52  |  Source: community
    ──────────────────────────────────────────────
    Use @paypal/react-paypal-js on the frontend with Smart Buttons.
    Backend creates and captures orders via REST API v2.
    Handles 3D Secure and buyer authentication automatically.

[2] PayPal webhook verification in Express
    Confidence: 79%  |  Validations: 34  |  Source: community
    ──────────────────────────────────────────────
    Verify webhook signatures server-side to confirm payment events.
    Use the verify-webhook-signature API endpoint, not local crypto.

spark insights def456 0

Insight: PayPal Checkout REST API v2 with Express

Architecture:
  - POST /api/orders         → creates a PayPal order
  - POST /api/orders/:id/capture → captures payment after buyer approval

Setup:
  1. Get client ID and secret from developer.paypal.com
  2. Generate access token via OAuth2 client_credentials grant
  3. Create order with POST /v2/checkout/orders
  4. Client redirects buyer to approval URL
  5. After approval, capture with POST /v2/checkout/orders/:id/capture

Key details:
  - Always use the /v2/ endpoints, not /v1/
  - Store credentials in environment variables, never in code
  - Use sandbox environment for testing (api-m.sandbox.paypal.com)
  - Production endpoint: api-m.paypal.com
  - Cache the access token (expires in ~9 hours)

Common mistakes:
  - Using the deprecated PayPal Node SDK (paypal-rest-sdk) instead of REST v2
  - Not caching the OAuth token (causes rate limiting)
  - Capturing payment before buyer approves (returns PAYER_ACTION_REQUIRED)

Tags: library:paypal-sdk, framework:express, task_type:integration, domain:api
Validated by: 68 developers
Last updated: 2026-01-30

// routes/paypal.js
import express from 'express';
 
const router = express.Router();
 
const PAYPAL_API = process.env.PAYPAL_API_URL; // api-m.sandbox.paypal.com
const CLIENT_ID = process.env.PAYPAL_CLIENT_ID;
const CLIENT_SECRET = process.env.PAYPAL_CLIENT_SECRET;
 
let cachedToken = null;
let tokenExpiry = 0;
 
async function getAccessToken() {
  if (cachedToken && Date.now() < tokenExpiry) return cachedToken;
 
  const response = await fetch(`${PAYPAL_API}/v1/oauth2/token`, {
    method: 'POST',
    headers: {
      'Authorization': `Basic ${Buffer.from(`${CLIENT_ID}:${CLIENT_SECRET}`).toString('base64')}`,
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: 'grant_type=client_credentials',
  });
 
  const data = await response.json();
  cachedToken = data.access_token;
  tokenExpiry = Date.now() + (data.expires_in * 1000) - 60000; // refresh 1min early
  return cachedToken;
}
 
router.post('/orders', async (req, res) => {
  const token = await getAccessToken();
  const response = await fetch(`${PAYPAL_API}/v2/checkout/orders`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${token}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      intent: 'CAPTURE',
      purchase_units: [{
        amount: { currency_code: 'USD', value: req.body.amount },
      }],
    }),
  });
 
  const order = await response.json();
  res.json(order);
});
 
router.post('/orders/:id/capture', async (req, res) => {
  const token = await getAccessToken();
  const response = await fetch(
    `${PAYPAL_API}/v2/checkout/orders/${req.params.id}/capture`,
    {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
    }
  );
 
  const capture = await response.json();
  res.json(capture);
});
 
export default router;

spark share def456 \
  --title "PayPal Checkout v2 Express integration" \
  --content "Complete PayPal Checkout integration using REST API v2 with Express.
 
Key implementation details:
1. Use /v2/checkout/orders endpoints (not deprecated v1 or NVP)
2. Cache the OAuth access token - it lasts ~9 hours and PayPal rate-limits token requests
3. Two-step flow: create order → redirect buyer → capture after approval
4. Use api-m.sandbox.paypal.com for testing, api-m.paypal.com for production
5. Always verify webhook signatures server-side for payment confirmation
 
Gotcha: if you get PAYER_ACTION_REQUIRED on capture, the buyer hasn't approved yet.
Gotcha: the old 'paypal-rest-sdk' npm package is deprecated — use direct REST calls." \
  --tag library:paypal-sdk \
  --tag framework:express \
  --tag task_type:integration \
  --tag domain:api