@papakweku/payment-sdk

Paystack wrapper for marketplace payments: subaccounts, transaction initialization with commission splits, verification, and webhook signature checks.

Install

npm install @papakweku/payment-sdk

Quick start

const { createPaymentSDK } = require('@papakweku/payment-sdk');

const sdk = createPaymentSDK({
  secretKey: process.env.PAYSTACK_SECRET_KEY,
  commissionRate: 0.04, // 4% platform fee (optional, default 0.04)
});

// Create merchant subaccount
const subaccount = await sdk.createSubaccount({
  businessName: 'My Store',
  settlementBank: '040100', // GCB Ghana
  accountNumber: '1011102865027',
  primaryContactEmail: '[email protected]',
  primaryContactName: 'Merchant Name',
  primaryContactPhone: '+233595802299',
});

// Initialize payment (amount in smallest unit: pesewas/kobo)
const payment = await sdk.initializeTransaction({
  email: '[email protected]',
  amount: 1000, // GHS 10.00
  subaccountCode: subaccount.data.subaccount_code,
  reference: 'txn_unique_ref_123',
  callbackUrl: 'https://yourapp.com/callback',
});

console.log(payment.data.authorization_url);

// Verify after payment
const verified = await sdk.verifyTransaction('txn_unique_ref_123');

// Verify webhook (use raw request body string)
const isValid = sdk.verifyWebhook(rawBody, req.headers['x-paystack-signature']);

API

createPaymentSDK(config)

| Option | Type | Default | Description | |--------|------|---------|-------------| | secretKey | string | required | Paystack secret key | | commissionRate | number | 0.04 | Platform commission (0–1) |

sdk.createSubaccount(options)

Creates a Paystack subaccount for split settlements.

sdk.initializeTransaction(options)

Initializes a Paystack checkout. Applies commission via transaction_charge when subaccountCode is provided.

Returns Paystack response plus split object:

{
  "totalAmount": 1000,
  "commission": 40,
  "merchantShare": 960,
  "commissionRate": 0.04,
  "merchantSharePercent": 96,
  "platformSharePercent": 4
}

sdk.verifyTransaction(reference)

Verifies payment status with Paystack.

sdk.verifyWebhook(payload, signature)

Validates x-paystack-signature using HMAC SHA-512.

sdk.calculateCommission(amount)

Calculates split without calling Paystack.

Publish to npm

1. Create an npm account at npmjs.com
2. Create an org or use your username scope if needed
3. Update name, repository, and homepage in package.json
4. Login and publish:

cd packages/payment-sdk
npm login
npm test
npm publish --access public

5. In your backend, replace the local link:

"@papakweku/payment-sdk": "^1.0.0"

License

MIT