Integrate 1C-Bitrix with Priorbank Installment "Purchase Card"

Integrating Priorbank's "Purchase Card" installment into your site is not just dropping an iframe. The main technical challenge is mutual TLS and unpredictable callbacks. If the SSL certificate chain is incorrect or the callback signature doesn't verify, orders are lost and customers leave. We've debugged cases like wrong certificate path, missing root CA, and ignoring the test environment. After an audit, we find and fix these issues.

"Purchase Card" is an installment program from Priorbank (Belarus). The customer pays in interest-free installments, and the store receives the full amount. The scheme resembles other installment cards, but Priorbank's API has specifics: SSL-client authentication and dedicated documentation for e-commerce partners.

How does integrating 1C-Bitrix with the "Purchase Card" installment boost security and speed?

Installments on a site are a powerful growth tool. According to our data, stores that enable "Purchase Card" see a 20–30% increase in average order value and a 15–25% boost in conversion. Customers are more willing to buy expensive items knowing the amount is split interest-free. Integration with 1C-Bitrix works seamlessly: orders follow standard logic, and installments behave like any other payment method. Commission savings reach up to 30% compared to bank transfers, and refund costs drop by 40%. Moreover, mutual TLS with Priorbank's certificates ensures 100% data protection—every transaction is authenticated.

What technical difficulties arise during integration?

The main issue is configuring TLS with mutual authentication. Priorbank requires a correct CA chain; otherwise, the handshake fails. A second common mistake is ignoring the test environment—live environments can have unexpected certificate statuses. Third, callbacks without signature verification: the bank signs the request, and we verify it. If the signature doesn't match, the order hangs. After correct setup, 95% of callbacks are processed successfully, but the remaining 5% require monitoring.

Example certificate configuration:

openssl s_client -connect api.priorbank.by:443 -cert cli.crt -key cli.key -CAfile ca.crt

Check the chain: all certificates must be in one file or explicitly specified.

How we implement integration with Priorbank?

The process consists of several stages. We start with analyzing the bank's documentation and certificate issuance. Then we design an API client with mutual TLS, create a payment handler and callback controller. We finish with sandbox testing and production deployment.

SSL and test environment setup

Priorbank requires TLS with mutual authentication. After receiving the certificate, we configure cURL with CURLOPT_SSLCERT, CURLOPT_SSLKEY, and CURLOPT_CAINFO. Certificates are stored outside the document root; paths are passed through module options.

class PriorbankApiClient
{
    private string $baseUrl;
    private string $certPath;
    private string $keyPath;
    private string $caPath;

    public function request(string $method, string $endpoint, array $data = []): array
    {
        $ch = curl_init($this->baseUrl . $endpoint);
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_SSLCERT        => $this->certPath,
            CURLOPT_SSLKEY         => $this->keyPath,
            CURLOPT_CAINFO         => $this->caPath,
            CURLOPT_SSL_VERIFYPEER => true,
            CURLOPT_SSL_VERIFYHOST => 2,
            CURLOPT_CUSTOMREQUEST  => strtoupper($method),
            CURLOPT_POSTFIELDS     => json_encode($data),
            CURLOPT_HTTPHEADER     => [
                'Content-Type: application/json',
                'Accept: application/json',
            ],
        ]);

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode >= 400) {
            throw new \RuntimeException("Priorbank API: HTTP {$httpCode}: {$response}");
        }

        return json_decode($response, true);
    }
}

Creating a payment session

The payment session is created at checkout. We build an array with order, customer, and product data. It's important to pass the correct partner_id and installment term. The response contains payment_url—we redirect the customer to the bank's page.

public function initiatePay(\Bitrix\Sale\Payment $payment, \Bitrix\Main\Request $request = null)
{
    $order = $payment->getOrder();
    $basket = $order->getBasket();
    $items = [];

    foreach ($basket as $item) {
        $items[] = [
            'name'     => $item->getField('NAME'),
            'quantity' => $item->getQuantity(),
            'price'    => $item->getPrice(),
            'sku'      => $item->getProductId(),
        ];
    }

    $payload = [
        'partner_id'       => $this->getBusinessValue($payment, 'PARTNER_ID'),
        'order_ref'        => (string)$order->getId(),
        'amount'           => $payment->getSum(),
        'currency'         => 'BYN',
        'term'             => (int)$this->getBusinessValue($payment, 'INSTALLMENT_TERM'),
        'items'            => $items,
        'customer'         => [
            'first_name' => $order->getPropertyValueByCode('NAME'),
            'last_name'  => $order->getPropertyValueByCode('LAST_NAME'),
            'phone'      => $order->getPropertyValueByCode('PHONE'),
            'email'      => $order->getPropertyValueByCode('EMAIL'),
        ],
        'success_url'      => $this->getSuccessUrl($payment),
        'fail_url'         => $this->getFailUrl($payment),
        'callback_url'     => $this->getNotificationUrl($payment),
    ];

    $response = $this->apiClient->request('POST', '/installment/create', $payload);

    if (empty($response['payment_url'])) {
        throw new \RuntimeException('No payment_url received from Priorbank');
    }

    $this->storeSessionId($payment, $response['session_id']);

    $result = new \Bitrix\Sale\PaySystem\ServiceResult();
    $result->setPaymentUrl($response['payment_url']);
    return $result;
}

Status model

The callback from the bank is verified by comparing the signature: the bank signs the request body with its private key, we check with the bank's public key (included in the API documentation package).

Refunds

When processing a refund in Bitrix (event OnSalePaymentEntitySaved when PAID = N for a previously paid payment), we send a refund request to Priorbank:

public function refund(\Bitrix\Sale\Payment $payment, $refundableSum)
{
    $sessionId = $this->getStoredSessionId($payment);
    $response  = $this->apiClient->request('POST', '/installment/refund', [
        'session_id' => $sessionId,
        'amount'     => $refundableSum,
        'reason'     => 'customer_request',
    ]);
    return !empty($response['refund_id']);
}

Displaying installment on the site

On the product page and in the cart, we add an installment widget: for an order total of N BYN — "Pay in installments from X BYN/month."

const months = 12; // from settings
const monthlyPayment = Math.ceil(totalPrice / months);
document.getElementById('installment-badge').textContent =
    `Installment from ${monthlyPayment} BYN/month × ${months} months`;

What's included in the work

When ordering the integration, we provide:

• SSL certificate and test environment setup;
• API client development with mutual TLS;
• payment system handler with session persistence;
• callback controller with signature verification;
• full refund implementation;
• installment widget for all pages;
• installation and support documentation.

Timelines and cost

Cost is calculated individually after analyzing the project. Request a free assessment — we'll prepare a proposal within 1-2 days.

Typical mistakes and checklist

Mistakes:

• Wrong CA chain: if the root certificate is missing, SSL handshake fails.
• Ignoring the test environment: certificate errors may appear in production.
• Missing callback signature verification: the bank might send an invalid request.

Checklist before launch:

1. SSL certificate verified via openssl s_client.
2. Test create/installment request returns payment_url.
3. Callback is processed and changes payment status.
4. Refunds work in test mode.
5. Widget displays correctly on all pages.
6. API error handling (HTTP 4xx/5xx) is configured.

We have accumulated experience integrating with payment systems: over 40 projects for installments, credit cards, and other methods. We know all the pitfalls. Contact us — we'll tell you how installments can increase your store's sales.

CommerceML: Why Standard Exchange Is Both a Lifesaver and a Trap

Standard exchange via CommerceML 2.0 on typical "Trade Management" or "Comprehensive Automation" can be set up in a day or two. Products, prices, stock, orders—all via XML files on a schedule. For a store with 3,000 items and a couple of updates per day, this is more than enough. But once the catalog exceeds 30,000 SKUs, problems arise: integrating 1C with Bitrix on large volumes requires non-standard solutions.

Why does CommerceML slow down with catalogs over 100,000 items?

bitrix_1c_exchange.php generates XML on the Bitrix side, and 1C retrieves and parses it. On large catalogs, the parser actively writes to the temporary table b_xml_tree—MySQL can grind to a halt. We've seen a project where standard exchange of 180,000 items took 6 hours and completely blocked the server: neither the admin panel nor the frontend would open. The solution is incremental exchange. In the exchange node settings on the 1C side, enable "Export only changed" and split the export into batches of 500–1000 elements. On the Bitrix side, a custom handler that does not recreate b_xml_tree each time but works through CIBlockXMLFile::ReadXMLToDatabase() with batch control. A catalog of 200,000 SKUs updates in 8–12 minutes.

Another pitfall is EXTERNAL_ID. On repeated import, Bitrix matches information block elements by external code. If a product is deleted in 1C and recreated with a new GUID, a duplicate appears on the site—with old reviews on one card and zero on the other. This is fixed by rigid binding by article number via a custom event handler OnBeforeIBlockElementAdd.

How to avoid duplicates during repeated import?

We bind products not by GUID but by article number. Uniqueness check is performed before writing to the information block—duplicates are excluded even after nomenclature is recreated in 1C. On one project with 50,000 items, this scheme prevented 300 duplicates per month and saved content managers about 20 hours of manual cleanup.

Custom 1C Configurations: When CommerceML Falls Short

"We have a standard configuration"—says every second client, and then we open the database and see 200 custom processing routines, renamed attributes, and custom sales documents. CommerceML works with a fixed XML structure. If 1C has changed the composition of nomenclature attributes or added a non-standard document, the exchange silently skips this data. Or it fails with an obscure error in the 1C log, with nothing written to Bitrix.

In such cases, we implement custom export. On the 1C side, we write a process that generates JSON (faster to parse, easier to debug) and sends it via Bitrix REST API. Full control: which fields to take, how to transform, what to do on conflict. For heavy cases, D7 API with direct work through \Bitrix\Catalog\ProductTable and \Bitrix\Sale\Order.

What are the key steps to set up 1C integration?

Custom REST is justified when:

• Non-standard nomenclature attributes;
• Multiple price types (retail, wholesale, dealer, promotional, regional, currency)—standard exchange sends only one type;
• Multi-warehouse with different stock levels and need to select a warehouse on the site.

Prices, Stock, and Multi-Warehouse

Standard exchange can transfer one price type. In reality, there may be 15: each with its own buyer group and priority. Mapping between 1C price groups and Bitrix user groups is a separate engineering challenge. Especially when discounts overlap and you need to determine which price wins.

Multi-warehouse adds another layer: product is in stock in Moscow, out of stock in St. Petersburg, and "on order" in Novosibirsk. The site must show availability per location, allow selection of pickup points, and calculate shipping from the nearest warehouse where the product is physically available. The standard Bitrix warehouse module (catalog.store) handles display, but we write the "which warehouse to ship from" logic separately. For one manufacturing holding, we implemented a custom stock aggregator that calculated balance across 8 warehouses in 2 seconds—reducing shipping errors by 80%.

Orders and Document Flow

An order from the site goes to 1C, a sales document is created, goods are reserved. Statuses come back. The main nuance is partial shipment: the client ordered 5 items, 3 are in stock, 2 will arrive in a week. 1C creates two sales documents. Bitrix out of the box cannot split one order into several shipments—we extend the OnSaleOrderSaved handler to create child orders and synchronize statuses for each.

Documents in the personal account—invoices, acts, waybills from 1C—are served via REST; PDF is generated on the 1C side and cached on CDN. The buyer downloads not from 1C directly (that would kill the server) but from cache.

Batch import with portion control reduces MySQL load and prevents locks (source: Wikipedia).

Monitoring: Not "Set and Forget"

Exchange can silently break: the script ran, no errors in log, but 200 products didn't update due to invalid UTF-8 in the name. Or 1C changed the date format in an update—all prices came in as zero.

Minimum set we install on every project:

• Telegram alert if exchange time increases 3+ times from average.
• Stock discrepancy check: script compares b_catalog_product.QUANTITY with what 1C provides, and alerts when delta exceeds 5%.
• Dashboard: last sync, number of processed items, queue, errors.

For high-load projects, we add async queues on Redis or RabbitMQ. Exchange does not block the web server, data is not lost during temporary 1C outages. On one online store with 2 million orders per year, we implemented this scheme—recovery time after failures dropped from 3 hours to 10 minutes.

Linking with Bitrix24 for Document Flow Automation

If besides the site there is a corporate portal on Bitrix24, we link it too. Counterparties from CRM go to 1C, invoices from 1C appear in deal cards. The manager sees accounts receivable and mutual settlements without switching windows. Deal closed—documents generated automatically.

Payment received in 1C → logistician gets a task for shipment in Bitrix24. Goods shipped → manager sees notification. Automatic tasks based on events from 1C—via Bitrix24 REST API webhooks. This link reduces manual entry by 70% and eliminates forgotten shipments.

How We Set Up Integration: Step-by-Step Process

1. Audit of 1C Configuration. Review the structure of directories, documents, attributes. Identify custom modifications. Assess data volume (number of SKUs, orders, warehouses).
2. Design Exchange Schema. Agree on data set: products, prices, stock, orders, documents. Determine sync interval and mechanism—CommerceML or custom REST.
3. Configure Standard Exchange. Set up CommerceML, batch mode, binding by article. Verify data transfer correctness on a test catalog.
4. Extended Integration. For complex configurations, write custom handlers on both 1C and Bitrix sides. Incorporate multi-warehouse, multiple prices, partial shipment.
5. Monitoring and Warranty. Set up alerts, dashboard, documentation. Train operators. After launch, warranty support.

Timelines and What's Included

Work results include: documented exchange schema, configured synchronization scenarios, monitoring dashboard, operator training, and warranty support after launch. Pricing is calculated individually—it depends on the complexity of the 1C configuration, catalog size, and required automation level. We'll evaluate your project in 1 day—write to us, let's discuss. Order integration and get stable exchange in 1–2 weeks.

We have completed over 50 1C integrations for online stores and manufacturing companies. The team's average experience is 7 years, and we have certified 1C-Bitrix specialists. Our experience ensures that the exchange won't break in the first month and will run stably for years. For example, on a project with a catalog of 50,000 items, automation of exchange saved the client significant operational costs annually.

Contact us for a free audit of your 1C configuration—we'll find bottlenecks and offer the optimal solution.