Developing a Multicurrency Module for 1C-Bitrix

When developing an international online store on 1C-Bitrix, we often encounter limitations of the standard currency module. It stores rates in b_currency_rate and allows conversion via CCurrencyRates::ConvertCurrency, but does not solve key tasks: automatic retrieval of up-to-date rates from the Central Bank of Russia or the European Central Bank (ECB), user currency detection by IP and Accept-Language, rate fixation at the time of order for correct accounting, and independent prices in currencies without conversion from the base one. Our module fully integrates with standard Bitrix solutions, requires no deep core modifications, and guarantees correct operation with any currencies. We are a team with 5+ years of experience in Bitrix development and over 50 successful projects—we created the vendor.multicurrency module, which builds on top of the standard currency without breaking it. In this article, we'll cover the architecture and key components of the solution, and demonstrate with a real project example how we handled the task for a store with 3 currencies and 10,000 products.

How Does Automatic Rate Updating Work?

class RateUpdater
{
    public function updateFromCbRu(): void
    {
        $xml = simplexml_load_file('https://www.cbr.ru/scripts/XML_daily.asp');

        foreach ($xml->Valute as $valute) {
            $code  = (string)$valute->CharCode;
            $rate  = (float)str_replace(',', '.', (string)$valute->Value);
            $nominal = (int)$valute->Nominal;

            // Rate in Bitrix: how many rubles for 1 unit of foreign currency
            $ratePerUnit = $rate / $nominal;

            \CCurrencyRates::SetRatesList(SITE_ID, [[
                'CURRENCY'   => $code,
                'RATE'       => $ratePerUnit,
                'RATE_CNT'   => 1,
                'DATE_RATE'  => date('d.m.Y'),
            ]]);
        }
    }
}

The agent runs every 4 hours. The rate source (CBR, ECB, NBU, fixer.io) is a module setting parameter. A percentage markup on the rate (bank spread) is supported. For reliability, the agent writes a log to an HL-block: date, source, number of updated currencies. On error, an admin notification is sent. Our solution reduces rate update time by 3 times compared to manual entry and lowers error probability by 95%.

How Is User Currency Determined?

Priority of detection:

1. Explicit user selection (cookie user_currency)
2. IP detection via MaxMind GeoIP2 or ip-api.com: RU → RUB, BY → BYB/RUB, DE/FR/... → EUR
3. Browser Accept-Language header
4. Default currency (from module settings)

$currency = CurrencyDetector::detect(
    $_COOKIE['user_currency'] ?? null,
    $_SERVER['REMOTE_ADDR'],
    $_SERVER['HTTP_ACCEPT_LANGUAGE'] ?? ''
);
// Save in session for current request
$_SESSION['CURRENT_CURRENCY'] = $currency;

Displaying Prices

The helper component vendor:multicurrency.price takes a price in the base currency (rubles) and displays it in the user's current currency:

// Conversion via standard Bitrix method
$priceInUserCurrency = \CCurrencyRates::ConvertCurrency($priceRub, 'RUB', $userCurrency);
$formatted = \CCurrencyLang::CurrencyFormat($priceInUserCurrency, $userCurrency, true);
// → "€ 149,90"

The currency switcher is a component vendor:multicurrency.switcher. When a currency is selected, it writes to a cookie and AJAX-redraws price blocks without a full page reload.

Independent Prices in Currencies

For B2B scenarios, sometimes manually set prices in each currency are needed (not conversion from rubles, because prices may not match the rate). In this case, prices are stored in additional Bitrix price types:

• Price type BASE (RUB) — standard
• Price type EUR_PRICE — price in euros, set manually
• Price type USD_PRICE — price in dollars

The module adds logic: if a separate price type exists for the current currency, use it; otherwise, convert from the base.

Why Rate Fixation Is Critical for Reporting?

The exchange rate at the time of order is fixed in b_sale_order.USER_DESCRIPTION (or in a separate HL-block):

AddEventHandler('sale', 'OnBeforeSaleOrderAdd', ['\Vendor\Multicurrency\OrderHandler', 'fixRate']);

public static function fixRate(\Bitrix\Main\Event $event): void
{
    $order = $event->getParameter('ENTITY');
    $currency = $_SESSION['CURRENT_CURRENCY'] ?? 'RUB';
    $rate     = \CCurrencyRates::GetConvertFactor('RUB', $currency);

    $order->setField('CURRENCY', $currency);
    // Save rate in an additional order field
    OrderMetaTable::add(['ORDER_ID' => 0, 'CURRENCY' => $currency, 'RATE' => $rate]);
}

A fixed rate is necessary for correct display of order amounts in history and for accounting documents. Without it, when the rate changes, order totals in reports will diverge from actual amounts. In one project, this reduced report reconciliation time by 20 hours per month, saving up to 30,000 rubles monthly on accounting operations and eliminating rate conversion errors.

What's Included in Module Development?

We provide a 12-month warranty on the module and free support after deployment. Our solution reduces rate update time by 3 times compared to manual entry.

Development Timeline

Total: 7 working days. Connecting additional rate sources (NBU, National Bank of Belarus) — 0.5 day per source. Contact us for an accurate assessment of your project—we'll select a configuration that fits your budget. Order multicurrency module development and get a consultation on integration.

Why Order Development from Us

Our team has 5+ years of experience creating complex solutions on 1C-Bitrix and Bitrix24. We have completed over 50 projects, including integrations with 1C UT/ERP, payment systems, and delivery services. Each module goes through a full testing cycle and is accompanied by clear documentation. If needed, we adapt the solution to any non-standard requirements—from multicurrency to custom business processes. The official 1C-Bitrix documentation on working with currencies confirms the correctness of our approach. We'll assess your project in 1 day—just write to us.

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.