Product Recommendation System for 1С-Bitrix

You are losing up to 30% of revenue if your 1С-Bitrix online store lacks personalized recommendations. A buyer comes for a specific product but sees no related items, receives no suggestions based on their interests—and leaves for a competitor. We solve this problem by implementing recommendation systems that increase the average order value by 15–25% and conversion to purchase. 10+ years of experience, certified specialists, guaranteed results.

Why Personalization Works So Well

Personalized recommendations work because they reduce cognitive load on the buyer. Instead of browsing hundreds of products, they see only relevant options. Algorithms analyze user behavior—views, cart additions, purchases—and select items likely to interest them. Compare: in our practice, collaborative filtering yields 30% higher CTR than content-based when there are 1000+ actions per product. McKinsey research shows that personalization increases revenue by 10-30%.

How Recommendation Algorithms Boost Conversion

The choice of algorithm determines recommendation accuracy. Let's look at the main approaches.

Content-based filtering—we recommend products similar to the viewed one by attributes: category, price, tags. Works without history, suitable for new users.

function getContentBasedRecommendations(int $productId, int $limit = 10): array {
    $product  = \CIBlockElement::GetByID($productId)->GetNext();
    $iblockId = $product['IBLOCK_ID'];
    $price    = \CPrice::GetBasePrice($productId)['PRICE'];
    $sectionId = $product['IBLOCK_SECTION_ID'];

    // Товары из той же категории в ценовом диапазоне ±30%
    $result = \CIBlockElement::GetList(
        ['RAND' => 'ASC'],
        [
            'IBLOCK_ID'          => $iblockId,
            'IBLOCK_SECTION_ID'  => $sectionId,
            '!ID'                => $productId,
            '>=CATALOG_PRICE_1'  => $price * 0.7,
            '<=CATALOG_PRICE_1'  => $price * 1.3,
            'ACTIVE'             => 'Y',
        ],
        false,
        ['nPageSize' => $limit],
        ['ID', 'NAME', 'DETAIL_PAGE_URL', 'PREVIEW_PICTURE']
    );

    $items = [];
    while ($item = $result->GetNext()) {
        $items[] = $item;
    }
    return $items;
}

The algorithm is simple to implement and works instantly, but does not consider individual user tastes.

Collaborative filtering—"users who viewed this product also viewed..." Requires accumulated view and purchase history, but provides more personalized recommendations. We collect data from:

• b_sale_basket and b_sale_order—real purchases.
• Custom table custom_product_views—product page views.
• b_sale_fuser—guest users.

Collaborative filtering performance is 30% higher than content-based in terms of CTR when there are 1000+ actions per product.

Matrix factorization (ALS/SVD)—advanced algorithm, requires libraries (Python: implicit, surprise). We offload recommendation calculation to a separate Python microservice, results are stored in Redis/PostgreSQL, Bitrix only reads them. This approach gives up to 12% CTR increase on large catalogs.

Collecting Behavioral Data

// Трекинг просмотра товара
// Вызывается в шаблоне компонента catalog.element
$userId  = $USER->GetID() ?: 0;
$fuserId = (int)\Bitrix\Sale\Fuser::getId();

$db->query("
    INSERT INTO custom_product_views (product_id, user_id, fuser_id, viewed_at)
    VALUES (?, ?, ?, NOW())
    ON DUPLICATE KEY UPDATE view_count = view_count + 1, viewed_at = NOW()
", [$productId, $userId, $fuserId]);

CREATE TABLE custom_product_views (
    id         SERIAL PRIMARY KEY,
    product_id INT NOT NULL,
    user_id    INT DEFAULT 0,
    fuser_id   INT NOT NULL,
    view_count INT DEFAULT 1,
    viewed_at  DATETIME,
    UNIQUE KEY uk_product_fuser (product_id, fuser_id),
    INDEX idx_fuser (fuser_id),
    INDEX idx_product (product_id)
);

Calculating "Users Also Viewed"

-- Товары, которые чаще всего смотрят вместе с товаром $productId
SELECT
    v2.product_id,
    COUNT(DISTINCT v2.fuser_id) AS co_views
FROM custom_product_views v1
JOIN custom_product_views v2
    ON v1.fuser_id = v2.fuser_id
    AND v2.product_id != v1.product_id
    AND v2.viewed_at BETWEEN DATE_SUB(v1.viewed_at, INTERVAL 1 HOUR)
                         AND DATE_ADD(v1.viewed_at, INTERVAL 1 HOUR)
WHERE v1.product_id = :productId
GROUP BY v2.product_id
ORDER BY co_views DESC
LIMIT 20;

Results are cached in Redis for 6–24 hours. They are recalculated by a Bitrix agent nightly for all popular products.

Personalization for Authorized Users

For authorized users, we look at view history over the last 30 days:

function getPersonalizedRecommendations(int $userId, int $limit = 12): array {
    // Последние просмотренные категории пользователя
    $recentCategories = getRecentUserCategories($userId, 5);

    // Товары из этих категорий, которые он ещё не смотрел
    return \CIBlockElement::GetList(
        ['CATALOG_PRICE_1' => 'ASC'],
        [
            'IBLOCK_ID'         => CATALOG_IBLOCK_ID,
            'IBLOCK_SECTION_ID' => $recentCategories,
            '!ID'               => getViewedProductIds($userId),
            'ACTIVE'            => 'Y',
        ],
        false,
        ['nPageSize' => $limit],
        ['ID', 'NAME', 'DETAIL_PAGE_URL', 'PREVIEW_PICTURE']
    );
}

Administrative Management of Recommendations

The system allows:

• Viewing click statistics on recommendations (CTR per algorithm).
• Adding manual recommendations (pinned) for specific products.
• Excluding products from recommendations (sold out, seasonal).
• A/B testing algorithms: half of users see content-based, half collaborative.

Approach Comparison: Time and Effect

Timeline

Total: 2.5–3.5 weeks for a full system. Content-based recommendations without personalization—1 week.

What's Included in the Work

• Documentation of recommendation API and data schema.
• Access to recommendation admin panel.
• Staff training (administration, A/B tests).
• 2 months of support after launch (bug fixes, fine-tuning).

Our Implementation Process: Step-by-Step

1. Data analysis—assess catalog size, view and purchase history, identify target pages for recommendation placement.
2. Algorithm selection—based on analysis, choose content-based, collaborative, or hybrid approach. For small stores, content-based often suffices; for large ones, collaborative filtering with collaborative filtering.
3. Data collection integration—implement tracking of views and purchases via custom tables and Bitrix events.
4. Development of recommendation blocks—create components for output on catalog, product card, and cart.
5. Caching and agents—set up Redis for fast access and Bitrix agents for nightly recalculation.
6. A/B testing—launch testing of different algorithms to gather statistics.
7. Deployment and training—deploy to production, train staff on admin panel usage.

Order development of a recommendation system and increase sales. Our team has implemented recommendation systems for 20+ online stores on Bitrix. We will evaluate your project in one working day. Get a consultation—contact us for cost and timeline estimates.

1C-Bitrix Module Development and Setup

The main trap of Bitrix is init.php. You add an OnBeforeIBlockElementUpdate handler there, then another one — a year later the file is 2000 lines, and on every hit all that code executes. We move business logic into full-fledged modules with D7 ORM, custom tables, and administrative interface. The module can be disabled, transferred to another project, covered with tests — none of that is possible with init.php. Our team has 10+ years of Bitrix experience, certified specialists, and a 6-month code guarantee. Request a consultation — we'll explain how to migrate legacy code to a modular architecture.

Why is init.php the worst place for business logic?

Init.php does not support class autoloading, lacks an isolated namespace, cannot be unit tested, and cannot be disabled without editing the file itself. Every handler written there runs on every request, even if not needed. In a module, you register handlers through EventManager, and they only execute when the event occurs. Performance difference: up to 3x with 10+ handlers.

Standard Modules: Typical Problems and Solutions

Information blocks. IBlock architecture is the first thing we review on any project. A classic mistake: one catalog infoblock with 80 properties, 30 of which are multiple. The b_iblock_element_property table swells to millions of rows, and CIBlockElement::GetList with filtering on three properties does a full scan. We move reference data to Highload-blocks, eliminate multiple properties where possible, and design the structure for 5x growth.

e-Store (sale). Cart business rules are a separate story. We set discount priorities to prevent two campaigns from giving 60% instead of 30%, connect payment handlers, and write custom validation via OnSaleOrderBeforeSaved.

Search. The built-in search module with morphology works up to 10–15 thousand elements. Beyond that — Elasticsearch. We configure it via the Bitrix search module API, indexing through CSearchFullText or custom indexers.

Highload-blocks for dictionaries, logs, user data — instead of bloated IBlocks. Direct queries via Bitrix\Highloadblock\HighloadBlockTable, custom tables instead of the EAV structure of standard infoblocks. A million records — no degradation.

Mail events. Configuration is not just templates in b_event_message. The key is SPF, DKIM, DMARC on the DNS, otherwise transactional emails go to spam. We check deliverability and set up bounce handling.

How to Design Infoblocks for Performance?

We use Highload-blocks for reference data (colors, sizes, manufacturers) that are not involved in complex queries. For SKUs — a separate infoblock with linking via IBLOCK_ELEMENT_PROPERTY. Enable INDEX_PROPERTY for frequently filtered properties. Tagged caching: when an element changes, only the related cache is cleared. Highload-blocks process up to 10x faster than infoblocks with multiple properties on volumes of 100,000 records.

Custom Module Development

Each module follows the structure /local/modules/vendor.modulename/:

• install/index.php — setup class, create tables via $DB->RunSQLBatch()
• lib/ — D7 ORM classes, extending Bitrix\Main\ORM\Data\DataManager
• admin/ — administrative pages using CAdminList, CAdminForm
• include.php — autoloading, event handler registration via EventManager::getInstance()->registerEventHandler()
• REST API endpoints via \Bitrix\Rest\RestManager

The module registers in the system, appears in the "Installed Solutions" list, and has its own settings at /bitrix/admin/settings.php?mid=vendor.modulename. It can be enabled, disabled, and updated through UpdateSystem or custom migration mechanics.

Examples of implemented tasks:

• Campaign management — visual condition builder via CAdminCalendar, timers via agents (CAgent::AddAgent), analytics linked to the sale module
• Cost calculator — React widget on the frontend, REST API in the module, formulas stored in a Highload-block
• Booking system — real-time calendar, locking via $DB->StartTransaction() / $DB->Commit() on concurrent requests, integration with channel manager via webhook

Components and Composite Cache

Component customization via result_modifier.php and component_epilog.php, not by editing template.php of the standard template. This way core updates are painless.

Composite cache ("Composite Site" technology) — the server sends ready HTML, bypassing PHP routing. Dynamic areas (cart, authorization) are loaded via CBitrixComponent::setFrameMode(true) and AJAX. TTFB drops to 30–50 ms. But there are caveats: not all components are compatible, $APPLICATION->ShowPanel() breaks composite, and careful markup of <div id="bx-composite-..."> is required.

What to Check Before Installing a Marketplace Module?

Before installing a module from the marketplace, an audit is mandatory. We check: SQL queries without prepared statements (hello SQL injection), direct use of $_REQUEST without filtering, use of outdated kernel API instead of D7, conflicts with the composite cache module. A module with no updates for over a year and a few dozen installations is likely a problem on the next PHP update. A typical case: a module calls CIBlockElement::GetList with no cache reset — the site crashes with 5000 elements.

Migration to D7

When upgrading PHP or switching to a new edition — refactor outdated calls:

• CIBlockElement::GetList() → Bitrix\Iblock\Elements\ElementTable::getList()
• CSaleOrder::GetList() → Bitrix\Sale\Order::getList()
• CModule::IncludeModule() → Bitrix\Main\Loader::includeModule() Testing on staging, rollback via git on issues.

According to official 1C-Bitrix documentation, D7 ORM is the recommended tool for working with data, providing type safety and automatic query generation.

Comparison: Init.php vs Module

Module Development Scope and Cost

What is included in module development?

• Technical specification and architectural plan
• Code following PSR-4 and Bitrix code style
• Unit tests (PHPUnit) for business logic
• Integration tests for events and REST API
• Installation, configuration, and API documentation
• Repository and documentation access
• Administrator training for module usage
• 6-month warranty support

Estimated timelines and complexity:

Cost is calculated individually — contact us for a project estimate.

Module Testing

Unit tests via PHPUnit cover business logic: discount calculation, validation, document generation. Mocks for Bitrix\Main\Application::getConnection() allow tests to be DB-independent. Integration tests verify event handlers on a real database — OnAfterIBlockElementAdd, OnSaleOrderSaved, etc. REST API endpoints are tested via curl or PHPUnit HTTP client. Critical for modules working with b_sale_order, b_catalog_price — where errors cost money.

Compatibility is checked on PHP 7.4, 8.0, 8.1, 8.2 and editions: Standard, Small Business, Business. We check conflicts with popular marketplace modules — they often intercept the same events. Load testing: measurements on 10K, 100K, 1M records, profiling via Xdebug for memory leaks and N+1 queries.

Practical Examples

Campaign module for an electronics chain. The built-in sale module discounts did not cover scenarios like "2+1", a gift with purchase over a certain amount, or combined conditions. We built a visual builder: marketers create rules via drag-and-drop without development tickets. Campaign calendar, auto-deactivation via agents, analytics linked to b_sale_order — conversion, average check, usage count. Time to launch a new campaign dropped from two days to half an hour.

Calculator for builders. Parameters (area, materials, number of floors) → formula → preliminary estimate → lead to CRM via CRest::call('crm.lead.add'). Regional coefficients and seasonal markups from a Highload-block, material prices from 1C exchange. The number of target leads increased by a third: clients see a breakdown before calling a manager.

Booking for a hotel chain. Real-time availability via AJAX requests to a custom table vendor_booking_slots, seasonal tariff calculation, synchronization with Booking.com via channel manager API. Room locking on concurrent booking via SELECT ... FOR UPDATE in transactions. Timezones handled via \DateTimeZone — a guest from Vladivostok and a manager from Moscow see the same picture.

We will evaluate your project within one day. Write to us — we'll tell you what is included in turnkey development. Contact us for a consultation on your project. Order a custom module development — get a ready solution with documentation and support.