@mongolian-payment/paylink

PayLink card payment SDK for Node.js — create invoices, query transactions, run reports.

Part of the mongolian-payment SDK suite. Also available for Python: mongolian-payment-paylink (source).

Wraps the PayLink External API (single POST /external/process endpoint, process-code driven).

Installation

npm install @mongolian-payment/paylink

Requires Node.js >= 18.0.0 (uses native fetch and node:crypto).

Quick Start

import { PayLinkClient } from '@mongolian-payment/paylink';

const client = new PayLinkClient({
  baseUrl: 'https://paylink.mn/api/v1', // test: https://pay-link.fiba.mn/api/v1
  username: 'MERCHANT_USERNAME',
  signatureKey: 'YOUR_SIGNATURE_KEY',
});

const invoice = await client.createInvoice({
  amountTotal: 10000,
  countTotal: 1,
  amount: 10000,
  description: 'Order #123',
  merchantRef: 'ORDER-123',
});
console.log(invoice.paymentLink); // redirect the buyer here
console.log(invoice.invid);

// Look up an invoice and its transactions
const detail = await client.getInvoice(invoice.invid);
console.log(detail.status, detail.transactions);

Authentication & signing

Every request sends three headers: pc (process code), X-USERNAME, and X-SIGNATURE.

Note on the signature. PayLink's exact signing scheme is not published. By default this SDK signs the HMAC-SHA256 (hex) of the JSON request body, keyed by signatureKey. If PayLink specifies a different scheme, pass your own sign function — it receives the exact body string and returns the signature:

new PayLinkClient({
  baseUrl, username,
  sign: (body) => mySignature(body),
});

Environment Variables

PAYLINK_BASE_URL=https://paylink.mn/api/v1
PAYLINK_USERNAME=MERCHANT_USERNAME
PAYLINK_SIGNATURE_KEY=your-signature-key

import { PayLinkClient, loadConfigFromEnv } from '@mongolian-payment/paylink';
const client = new PayLinkClient(loadConfigFromEnv());

API Methods

| Method | Process code | Description | |--------|--------------|-------------| | createInvoice(input) | cu0900 | Create an invoice → CreatedInvoice | | listInvoices(input?) | cu0901 | List invoices | | getInvoice(invid) | cu0904 | Invoice detail incl. transactions | | cancelInvoice(invid) | cu0905 | Cancel an invoice | | batchMarkPaid(invid) | cu0906 | Batch mark an invoice paid | | invoiceReport(input?) | cu0907 | Paginated invoice report | | invoiceSummary(input?) | cu0908 | Invoice summary counters | | transactionReport(input?) | cu0909 | Paginated transaction report | | transactionSummary(input?) | cu0910 | Transaction summary counters |

List/report/summary results are returned as the API sends them (snake_case keys). createInvoice maps to a camelCase CreatedInvoice. Dates use the YYYY-MM-DD HH24:MI:SS format.

Endpoints

| Environment | Base URL | |-------------|----------| | Production | https://paylink.mn/api/v1 | | Test | https://pay-link.fiba.mn/api/v1 |

Error Handling

Every call returns HTTP 200; the result is driven by response_code (RC000000 = success). Non-success codes and transport errors throw PayLinkError:

import { PayLinkError } from '@mongolian-payment/paylink';

try {
  await client.getInvoice('INV-404');
} catch (err) {
  if (err instanceof PayLinkError) {
    console.error(err.message);       // "PayLink cu0904 failed: RC000015 - Record not found"
    console.error(err.responseCode);  // "RC000015"
    console.error(err.statusCode);    // set for HTTP-level failures
    console.error(err.response);      // raw response body
  }
}

License

MIT