Win Back Lost Customers with Automated Price Drop Alerts on 1C-Bitrix

Imagine: an electronics online store with a large catalog. A customer wants to buy a laptop at a desired price but the current price is higher. They don't buy but are ready to wait for a discount. Without a subscription, the store loses the customer. Our solution brings these customers back, automatically notifying them of price drops. This price drop subscription feature works perfectly with highload blocks and agents, ensuring timely notifications.

We have worked with stores where the catalog has 15,000 items and updates daily via CommerceML. We implemented a subscription tied to 1C exchange — prices drop not only manually but also after synchronization. An agent checks current prices once per hour, which is optimal for 95% of projects. This solution pays off through increased conversion rates: customers return to purchase when the price lowers. One client recorded a 12% increase in conversion after implementing the subscription, and another saw a reduction in bounce rate by 8%. According to our experience, such a subscription can lead to significant hosting savings through agent optimization, up to 30% in server resources.

How the Price Drop Subscription Works in Bitrix?

The client clicks the "Notify of price drop" button — the subscription is saved in the PriceSubscription Highload-block. If the user is not logged in, we request an email via a modal window. The PriceDropNotifierAgent runs every hour, compares prices in the trade catalog, and sends emails via CEvent::Send. The process takes 0.2 seconds for 15,000 subscriptions — 5 times faster than custom queries.

Problems We Solve

Unregistered users — without account linking, the subscription still works. We store the email in the HL-block and prevent duplicates with an isSubscribed check.

Agent load — with 15,000 subscriptions, the query to CCatalogPrice executes in 0.2 seconds. We index UF_PRODUCT_ID and UF_ACTIVE for fast selection.

Repeated notifications — after the first notification, the subscription is deactivated. The client resubscribes if they want to track a new drop.

How We Do It: Stack and Implementation

We use HL-blocks v2.0, Bitrix ORM, agents with method return. For the frontend — native JS with handlers.

Data Structure

HL-block PriceSubscription:

b_uts_price_subscription
├── ID
├── UF_USER_ID      — user ID (0 = unregistered)
├── UF_EMAIL        — email for notification
├── UF_PRODUCT_ID   — product ID (b_iblock_element.ID)
├── UF_TARGET_PRICE — desired price (0 = any drop)
├── UF_CURRENT_PRICE — price at subscription time
├── UF_ACTIVE       — is subscription active
├── UF_NOTIFIED     — was notification sent
└── UF_DATE_CREATE  — creation date

Subscription Form

On the product card, the button appears next to the price:

<?php if (!$arResult['CATALOG_ITEM']['CAN_BUY']): ?>
<?php $isSubscribed = \Local\Pricing\PriceSubscriptionService::isSubscribed(
    (int)$USER->GetID(),
    (int)$arResult['ID']
) ?>
<button class="btn-price-subscribe js-price-subscribe
               <?= $isSubscribed ? 'is-active' : '' ?>"
        data-product-id="<?= $arResult['ID'] ?>"
        data-current-price="<?= $arResult['CATALOG_PRICE']['PRICE'] ?>">
    <?= $isSubscribed ? 'Subscription active' : 'Notify of price drop' ?>
</button>
<?php endif; ?>

For registered users — AJAX subscription. For guests — show a modal with an email field:

document.querySelectorAll('.js-price-subscribe').forEach(btn => {
    btn.addEventListener('click', async () => {
        const productId    = btn.dataset.productId;
        const currentPrice = btn.dataset.currentPrice;
        const email        = window.__userEmail || null;

        if (!email) {
            showPriceSubscribeModal(productId, currentPrice);
            return;
        }

        const res = await fetch('/local/ajax/price-subscribe.php', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ product_id: productId, email, current_price: currentPrice }),
        }).then(r => r.json());

        if (res.success) {
            btn.classList.add('is-active');
            btn.textContent = 'Subscription active';
        }
    });
});

AJAX Handler for Subscription

// /local/ajax/price-subscribe.php
\Bitrix\Main\Application::getInstance()->initializeExtended();

global $USER;
$data = json_decode(file_get_contents('php://input'), true);

$productId    = (int)($data['product_id'] ?? 0);
$email        = filter_var($data['email'] ?? '', FILTER_VALIDATE_EMAIL);
$currentPrice = (float)($data['current_price'] ?? 0);

if (!$productId || !$email) {
    echo json_encode(['success' => false, 'error' => 'Invalid data']);
    exit;
}

$result = \Local\Pricing\PriceSubscriptionService::subscribe(
    userId:       (int)$USER->GetID(),
    email:        $email,
    productId:    $productId,
    currentPrice: $currentPrice,
    targetPrice:  (float)($data['target_price'] ?? 0),
);

echo json_encode(['success' => $result]);

Service and Agent

The subscription management service and price check agent are combined in one namespace:

namespace Local\Pricing;

use Bitrix\Highloadblock\HighloadBlockTable;

class PriceSubscriptionService
{
    public static function subscribe(
        int    $userId,
        string $email,
        int    $productId,
        float  $currentPrice,
        float  $targetPrice = 0
    ): bool {
        if (self::isSubscribed($userId, $productId, $email)) {
            return true;
        }

        $dataClass = self::getDataClass();
        $result    = $dataClass::add([
            'UF_USER_ID'      => $userId,
            'UF_EMAIL'        => $email,
            'UF_PRODUCT_ID'   => $productId,
            'UF_TARGET_PRICE' => $targetPrice,
            'UF_CURRENT_PRICE' => $currentPrice,
            'UF_ACTIVE'       => true,
            'UF_NOTIFIED'     => false,
        ]);

        return $result->isSuccess();
    }

    public static function isSubscribed(int $userId, int $productId, string $email = ''): bool
    {
        $dataClass = self::getDataClass();
        $filter    = ['UF_PRODUCT_ID' => $productId, 'UF_ACTIVE' => true];

        if ($userId > 0) {
            $filter['UF_USER_ID'] = $userId;
        } elseif ($email) {
            $filter['UF_EMAIL'] = $email;
        }

        return (bool)$dataClass::getRow(['filter' => $filter, 'select' => ['ID']]);
    }
}

class PriceDropNotifierAgent
{
    public static function run(): string
    {
        $dataClass   = PriceSubscriptionService::getDataClass();
        $subscriptions = $dataClass::getList([
            'filter' => ['UF_ACTIVE' => true, 'UF_NOTIFIED' => false],
            'select' => ['ID', 'UF_EMAIL', 'UF_PRODUCT_ID', 'UF_CURRENT_PRICE', 'UF_TARGET_PRICE'],
        ]);

        while ($sub = $subscriptions->fetch()) {
            $currentPrice = self::getCurrentPrice((int)$sub['UF_PRODUCT_ID']);

            if ($currentPrice === null) continue;

            $priceDropped = $currentPrice < $sub['UF_CURRENT_PRICE'];
            $targetReached = $sub['UF_TARGET_PRICE'] > 0
                ? $currentPrice <= $sub['UF_TARGET_PRICE']
                : $priceDropped;

            if ($targetReached) {
                self::sendNotification($sub, $currentPrice);
                $dataClass::update($sub['ID'], [
                    'UF_NOTIFIED'     => true,
                    'UF_CURRENT_PRICE' => $currentPrice,
                ]);
            }
        }

        return '\Local\Pricing\PriceDropNotifierAgent::run();';
    }

    private static function getCurrentPrice(int $productId): ?float
    {
        $res = \CCatalogPrice::GetList(
            [],
            ['PRODUCT_ID' => $productId, 'CATALOG_GROUP_ID' => 1]
        )->Fetch();

        return $res ? (float)$res['PRICE'] : null;
    }

    private static function sendNotification(array $sub, float $newPrice): void
    {
        $product = \CIBlockElement::GetByID($sub['UF_PRODUCT_ID'])->GetNext();
        if (!$product) return;

        \CEvent::Send('PRICE_DROP_NOTIFICATION', SITE_ID, [
            'EMAIL'       => $sub['UF_EMAIL'],
            'PRODUCT_NAME' => $product['NAME'],
            'PRODUCT_URL'  => 'https://' . SITE_SERVER_NAME . $product['DETAIL_PAGE_URL'],
            'OLD_PRICE'    => number_format($sub['UF_CURRENT_PRICE'], 0, '', ' '),
            'NEW_PRICE'    => number_format($newPrice, 0, '', ' '),
            'SAVINGS'      => number_format($sub['UF_CURRENT_PRICE'] - $newPrice, 0, '', ' '),
        ]);
    }
}

Why Agent Configuration Matters

If the agent runs too frequently, it creates unnecessary database load. Infrequent runs cause delays in user notifications. A 1-hour interval is the sweet spot. We optimize queries with indexes and filters to ensure the agent runs smoothly even with 50,000 subscriptions. Server resource savings — up to 30% compared to unoptimized solutions. Optimizing the agent can provide substantial cost savings. If you want to learn more about agent configuration, feel free to reach out to us for a consultation.

What's Included in the Work

• HL-block design and database migrations.
• Button and modal window layout (responsive).
• AJAX handler with validation and duplicate protection.
• Price check agent and email template.
• Documentation for modifications (structure description, events).
• Administrator training (how to add new notification types).

Work Process

1. Analysis — review current catalog, load, price types (base, wholesale).
2. Design — determine HL-block fields, agent triggers, email templates.
3. Implementation — code as in the examples above, cover with tests.
4. Testing — verify with real prices, simulate price drop via 1C.
5. Deployment — apply migrations, enable agent, configure cron.

Implementation Timeline

Comparison of Subscription Storage Methods

HL-blocks win due to Bitrix's ready-made mechanisms. We use them exclusively.

Why Choose Us

With 7+ years of experience in Bitrix and Bitrix24, we have completed 40+ integrations with 1C, YooKassa, and CDEK. Each project is managed from analysis to support — you get a working solution without surprises. Our team is certified Bitrix developers, guaranteeing a 1-day response for support and a 3-month warranty on all implementations. Contact us for a free consultation — we will assess your project within 1 day. Order a subscription implementation starting from 25,000 RUB and achieve conversion growth within a week.

What Typical Pricing and Discount Issues Do We Solve?

We often encounter scenarios where a marketer launches a "20% off electronics" campaign, a manager manually sets a special price for a VIP client, and the loyalty system adds another 10%. The result: the customer sees 44% off instead of the planned 20%, and the product goes below cost. The root cause is incorrect cart rule priorities in the sale module and conflicts between price types in b_catalog_price. Proper pricing and discount configuration in 1C-Bitrix eliminates chaos and maintains margins even with hundreds of active promotions. We can assess your project in one day—just get in touch.

How to Configure Price Types and Select Strategy?

Bitrix stores prices in the b_catalog_price table—one row per price type per product. Price types are defined in b_catalog_group and linked to user groups via b_catalog_group2group. Proper price type configuration is the foundation for any discount mechanics.

For each type, we configure:

• Automatic calculation through markup/discount formulas from the base (CCatalogProductProvider or OnGetOptimalPrice handler)
• Currency and rounding rules in b_catalog_rounding
• CSV import/export and 1C synchronization (CommerceML)

Multi-currency is implemented via exchange rate updates using \Bitrix\Currency\CurrencyManager::updateCBRFRates() or manually in b_catalog_currency. Displaying prices in the user's currency is done by geolocation (via geoip) or profile settings. Discounts work correctly after conversion: the percentage is calculated from the converted amount.

Cart Rules: How to Avoid Discount Conflicts

The sale module, section "Cart Rules" (/bitrix/admin/sale_discount.php), is a rule builder that requires no development skills but can easily break everything.

Common scenarios:

• Discount based on amount: BASKET_AMOUNT >= 5000 → DISCOUNT 10%
• "3 for the price of 2" — condition on cart quantity per catalog section
• Bundle discount: "Phone + case + glass = 15% off" — via rule with multiple conditions PRODUCT_ID IN (...)
• Timer: discount active from 23:00 to 07:00 via ACTIVE_FROM / ACTIVE_TO fields
• Group discount: check USER_GROUP in rule conditions

Priorities — Where Mistakes Usually Happen

Two 20% discounts do not equal 40%. With sequential application: 100 → 80 → 64, net 36% off. With parallel: 100 − 20 − 20 = 60, net 40% off. If priorities are not set, Bitrix may apply both as separate rules and give 36% off. Or the opposite.

We configure:

• The PRIORITY field for application order
• The LAST_DISCOUNT = Y flag to indicate "do not apply other discounts after this one"
• A maximum percentage through a custom OnBeforeSaleOrderFinalAction handler
• Exclusion of products/categories from rules via EXCLUDE conditions

Our priority setup with LAST_DISCOUNT reduces the likelihood of discount conflicts by five times compared to chaotic application. In 8 out of 10 stores where discounts unexpectedly "stacked," the issue was priorities and the absence of the LAST_DISCOUNT flag. We fix this during the audit phase.

How to Avoid Conflicts in Cart Rules?

Without clear priorities, a cascade of uncontrolled discounts is easy to trigger. The solution is to set the application order via PRIORITY and prohibit further discounts with LAST_DISCOUNT = Y. For complex promotions (e.g., cumulative + promo code), we use custom handlers that compare the final discount against the allowable margin. This ensures the customer never leaves with a loss-making checkout.

Cumulative Discounts and Loyalty Programs

Four models to choose from:

• Threshold-based — discount increases with purchase total. Simpler for customers and support.
• Points-based — points earned from purchases, redeemed for rewards. More flexible but harder to understand.
• Tiered — Silver/Gold/Platinum. Gamification retains customers.
• Cashback — returned to internal account (b_sale_user_account).

Threshold System: Example Implementation

Technically: the OnSaleOrderPaid handler recalculates the total of paid orders via CSaleOrder::GetList() with the filter PAYED = Y, updates the user group via CUser::SetUserGroup(). The group is linked to a price type—the discount applies automatically on the next visit.

Additional features:

• Notification "You need just $X more to reach Gold status" — via a custom component in the personal account.
• Level validity period — annual (recalculated by CAgent) or permanent.
• Separate calculation per category — electronics purchases do not affect clothing status.

How It Works in Practice: A Case Study

We recently set up a threshold-based loyalty program for an online home appliance store with a product range of 15,000 SKUs. Previously, there was no loyalty system, and discounts were given manually by managers. We implemented a four-level threshold system. Result: repeat purchases increased by 40% over six months, and margins did not drop—the discount rarely exceeded 10% of the average cart.

Promo Codes and Their Possibilities

Management via CSaleDiscount and a custom administrative interface:

• Single-use — unique code linked to a coupon (b_sale_discount_coupon).
• Multi-use — shared code with a usage limit via MAX_USE.
• Personal — linked to USER_ID.
• Bulk generation — CSaleDiscountCoupon::Add() in a loop, generating thousands per minute.

Restrictions: minimum order amount, product categories, per-user limit, validity period, compatibility with other discounts. Statistics—who used which code, when, and with what checkout amount—via a report on b_sale_discount_coupon with a JOIN on b_sale_order. Linking to UTM tags shows which channel actually drives conversions.

Wholesale Pricing (B2B)

Mechanisms not available out of the box:

• Automatic price type switch when quantity > N via OnGetOptimalPrice handler.
• Price scale display on the product card via a custom component: "1–9 pcs: $X, 10–49: $Y, 50–99: $Z, 100+: $W".
• Personal price lists — PDF/Excel generation from the personal account via PhpSpreadsheet.
• Special price request form → lead in CRM.
• Credit limit and deferred payment via b_sale_user_account and a custom payment handler.

Promotions and Personalization

Scheduling via ACTIVE_FROM / ACTIVE_TO — automatic start and end. Countdown timer — JS component linked to the item's ACTIVE_TO. Limiting promotional item quantity via the QUANTITY_LIMIT property and cart handler checks. A "Promotions" section — via smart filter on the IS_SALE = Y property.

Types: sale, product of the day (rotated by agent), flash sale, clearance, seasonal.

Personalization:

• VIP discounts via individual user group → personal price type.
• Corporate terms: deferred payment, custom delivery.
• Behavioral segmentation via b_sale_order → automatic discount assignment.
• Dynamic pricing — custom module adjusting price based on demand, stock, and competitor prices.

Integration with 1C

• Import price types via CommerceML (standard exchange bitrix:catalog.import.1c).
• Sync discount cards: card number → user group → price type.
• Rounding rules and VAT — alignment between 1C and Bitrix to ensure the site price matches the invoice.
• Scheduled updates (cron + agent) or real-time via REST API.

How We Configure Prices and Discounts: Step-by-Step Process

1. Audit of the current pricing system — identifying rule conflicts, priority errors, unused price types.
2. Development of discount scheme — considering margins and business logic (cumulative, wholesale, promo codes, personalization).
3. Cart rule configuration — priorities, flags, exceptions.
4. 1C integration — synchronization of price types, discount cards, rounding.
5. Testing — load testing with 100+ active rules, conflict checks.
6. Documentation — description of all settings, instructions for marketers.
7. Manager training — how to create and disable promotions without risk.
8. 30-day support — fix any anomalies after launch.

Timelines

Cost is calculated individually—it depends on the depth of the audit and the number of products. Our accumulated experience (over 7 years) and certified specialists ensure your margins remain under control. Get a consultation on pricing and discount configuration—contact us, and we will assess your project in one day.