Stock notification setup for 1C-Bitrix: custom subscription table

Custom stock notification for 1C-Bitrix: a practical guide

Picture this: a popular item is out of stock, and a potential buyer leaves without leaving their contact details. You lose sales, and customers get frustrated. 1C-Bitrix has no built-in "notify when available" feature — the standard subscription component isn't provided. We solve this with custom development, using a separate subscription table or the subscribe module. Savings from not buying a ready-made module can be significant, and the payback period is short.

Why the standard subscription module falls short

The subscribe module is designed for newsletters, and adapting it for product subscriptions is a compromise. Each product (or SKU) is registered as a "rubric", and a subscription is treated as a subscription to that rubric. When stock appears, you send an email manually or via an agent. Drawbacks: no direct link to a specific product, difficult management, risk of duplicate emails. For small stores with a dozen items, this might work, but for catalogs with thousands of positions, a custom subscription table is better. In one project, we saw the subscribe module send three identical emails to the same subscriber — because of missing uniqueness. After migrating to a custom table, the issue disappeared.

How to set up stock notifications

Option 1: Via the subscription module

The subscribe module can be adapted, but it requires extra logic. For example, when stock changes, an agent checks subscriptions for that product and sends emails. However, this approach lacks flexibility: you can't store send date, status, or guarantee uniqueness. The time spent on adaptation is roughly the same as for a custom table, but the result is inferior.

Option 2: Custom subscription table

This is the better solution — create a separate table product_availability_notify with fields PRODUCT_ID, EMAIL, USER_ID, DATE_ADD, DATE_SENT, IS_SENT. Uniqueness on product-email pairs prevents duplicates. The subscription form is a simple HTML+AJAX form that appears when QUANTITY = 0. When stock appears, the OnProductUpdate event handler triggers. See the official OnProductUpdate documentation.

Trigger for sending notifications

The OnProductUpdate event from the catalog module fires when the QUANTITY field changes. In the handler, we check if QUANTITY became greater than zero while it was zero before — then we select all subscribers and send emails via a mail event. Example code:

AddEventHandler('catalog', 'OnProductUpdate', function($productId, $fields) {
    if (isset($fields['QUANTITY']) && (float)$fields['QUANTITY'] > 0) {
        $subscribers = NotifyTable::getList([
            'filter' => ['=PRODUCT_ID' => $productId, '=IS_SENT' => false],
        ])->fetchAll();

        foreach ($subscribers as $subscriber) {
            \Bitrix\Main\Mail\Event::send([
                'EVENT_NAME' => 'PRODUCT_AVAILABLE_NOTIFY',
                'LID'        => SITE_ID,
                'C_FIELDS'   => [
                    'EMAIL'        => $subscriber['EMAIL'],
                    'PRODUCT_NAME' => $fields['NAME'],
                    'PRODUCT_URL'  => $fields['DETAIL_PAGE_URL'],
                ],
            ]);
        }
        NotifyTable::updateMulti(['IS_SENT' => true], ['PRODUCT_ID' => $productId]);
    }
});

Email template

Create a mail event type under Settings → Mail Events → Event Types. The event type PRODUCT_AVAILABLE_NOTIFY with fields EMAIL, PRODUCT_NAME, PRODUCT_URL. Configuration takes 1-2 hours.

Agent for periodic checks

If the OnProductUpdate event doesn't fire (e.g., stock is changed outside standard methods), set up a Bitrix agent that runs once an hour. It checks stock for products with active subscribers and sends emails. The agent is a reliable fallback.

Common mistakes during setup

Mistake #1: forgetting to clear the IS_SENT flag when stock reappears after being zero again. If a product goes out of stock and then becomes available again, the subscriber should receive a second notification. In our custom table, this is handled by resetting the flag when stock hits zero. Mistake #2: confusion with the SKU binding — we subscribe to a specific SKU, not the parent product. Mistake #3: incorrect mapping of mail fields — the email arrives with empty data. We catch all these during testing.

Setup steps and time estimates

What's included

• Subscription form (HTML + AJAX) on product page
• Custom subscription table with migration
• Event handler OnProductUpdate (or agent)
• Mail event and email template
• User documentation
• Admin training (30 minutes)
• 6-month warranty for correct operation

Timelines and cost

Basic setup (form + handler + email) takes 4–8 hours. If a subscription management page in the user account is needed, add 2-3 hours. The cost is calculated individually based on complexity, but the savings from avoiding a purchased module can be substantial. You get a stable, extensible solution.

Our experience: over 5 years of Bitrix development, 50+ e-store customisation projects. We can set up stock notifications turnkey with a guarantee of stable operation. Contact us to evaluate your project — get a free consultation.

How the agent works

The agent runs once an hour. It queries products that have subscribers with IS_SENT = false and checks their stock via CIBlockElement::GetList. If stock > 0, it sends emails using the same logic as the handler.

What Professional 1C-Bitrix Installation Includes

We start by checking innodb_buffer_pool_size. The default MySQL value (128 MB) is a death sentence for an online store with a catalog of 10,000+ items. We set 70–80% of available RAM on a dedicated server, 50% on VPS. This single setting speeds up the site by 2–3 times compared to the default. We'll assess your project in one day — get a consultation. Contact us to order turnkey installation with performance guarantee.

How to Choose Hosting and Edition for 1C-Bitrix Installation?

BitrixVM is a virtual machine with a pre-installed stack: nginx + Apache, PHP-FPM, MySQL/MariaDB, Sphinx, Push server. For VPS — the best start. Everything is already configured for Bitrix, including OPcache, log rotation, and firewall. Management via web panel on port 8890. Bitrix documentation recommends starting with BitrixVM for predictable performance.

VPS/VDS is the sweet spot. Minimum configuration for a medium online store: 2 vCPU, 4 GB RAM, SSD. Optimal: 4 vCPU, 8 GB RAM. OS: Ubuntu 22.04 or Debian 12. If not BitrixVM, we configure the stack manually for the task. Virtual hosting — only for business cards and landing pages. Requirements: PHP 8.0+, MySQL 5.7+ / MariaDB 10.0+, 512 MB RAM, .htaccess. 1C-Bitrix hosting partners guarantee compatibility. Dedicated server — for highload. Typical architecture: web server separate, database separate, Redis/Memcached separate. For Enterprise edition — web cluster with load balancer. Cloud (Yandex Cloud, VK Cloud, Selectel) — when load spikes: sales, seasonal peaks. Autoscaling via Managed Kubernetes or simple VM vertical scaling.

Choosing the edition is equally important. A common mistake: choosing "Small Business" for a store that grows to B2B with wholesale prices and three warehouses in six months. Upgrading to "Business" — pay the difference, data is not lost, but it's better to plan ahead. Our specialists select the edition for current tasks and with room for growth. For example, the "Business" license (about 35,000 RUB) pays off through multi-warehouse and 1C exchange, while the wrong choice can lead to a loss of up to 30,000 RUB monthly on excess resources.

What Server Settings Are Critical for 1C-Bitrix?

Web Server and PHP

nginx as reverse proxy + Apache (mod_php) or nginx + PHP-FPM directly. The second option saves memory — Apache is not needed. But some Bitrix modules use .htaccess, so for compatibility we sometimes keep Apache. nginx configuration: fastcgi_read_timeout 300 — for long operations (1C import), client_max_body_size 1024m — large file uploads. Block access to .settings.php, .settings_extra.php, bitrix/.settings.php — they contain database passwords. Rewrite rules from urlrewrite.php — Bitrix generates them, but with nginx + PHP-FPM they need to be duplicated. PHP 8.0–8.2 with extensions: mbstring, curl, gd, xml, json, opcache, redis/memcached. Key php.ini settings: opcache.memory_consumption=256, opcache.max_accelerated_files=20000, max_execution_time=300, memory_limit=512M, upload_max_filesize=100M, post_max_size=128M.

Database and Caching

MySQL/MariaDB. Key my.cnf parameters: innodb_buffer_pool_size — 70–80% RAM, innodb_log_file_size=256M, tmp_table_size=256M, max_heap_table_size=256M, thread_pool_size — number of CPU cores. Encoding utf8mb4 mandatory, otherwise emoji and special characters break. Redis is preferable to Memcached for Bitrix — supports persistent connections and is more reliable. In production, Redis handles concurrent writes three times faster than Memcached under typical load. Configure in .settings_extra.php:

'cache' => ['value' => ['type' => ['class_name' => '\\Bitrix\\Main\\Data\\CacheEngineRedis']]]
'session' => ['value' => ['mode' => 'default', 'handlers' => ['general' => ['type' => 'redis']]]]

sudo apt install redis-server
sudo systemctl enable redis

SSL, Email, and Cron

SSL — Let's Encrypt via certbot in 90% of cases. Redirect HTTP → HTTPS (301), HSTS, TLS 1.2/1.3, OCSP Stapling. In Bitrix, switch to HTTPS in the main module settings. Email: abandon mail() — connect SMTP (Yandex.Mail for domain, Mail.ru for Business). Be sure to configure SPF, DKIM, DMARC. Without SPF, emails go to spam. Test deliverability via mail-tester.com — score 9+/10. Cron: Bitrix agents switch to system cron — * * * * * /usr/bin/php /var/www/bitrix/modules/main/tools/cron_events.php. Schedule 1C exchange (15–60 min), search reindex, backups (mysqldump + rsync, rotation 7+4), temporary file cleanup.

Security and Administration

File system: owner www-data, directories 755, files 644, upload 775. nginx blocks access to configuration files. Enable Bitrix Proactive Protection — WAF, activity control (block after 5 failed attempts), kernel integrity check. For admin panel: two-factor authentication via Google Authenticator or OTP, restrict access by IP via nginx for paranoid.

How Long Does 1C-Bitrix Installation and Configuration Take?

Post-Installation Checklist

1. Performance Monitor (/bitrix/admin/perfmon_panel.php) — aim for 30+ points. Below 20 means serious configuration issues.
2. System Check — automatic check of all parameters. Red items must be fixed, yellow — case by case.
3. Security Scanner — check for typical vulnerabilities.
4. PageSpeed Insights — TTFB < 200ms on VPS, LCP < 2.5s.
5. Test 1C exchange — if integration is planned, verify CommerceML exchange before launch.

Additionally, check software versions, caching settings, cron operation, SSL certificate, SPF/DKIM/DMARC, access rights, delete default users and pages. For projects with 54-FZ, ensure fiscalization is configured via OFD provider.

Deliverables

• Fully configured server for 1C-Bitrix with MySQL, PHP, nginx optimization.
• Installed and activated license of the required edition.
• SSL certificate, email settings, cron and backups.
• Documentation: all configuration parameters, access credentials, cron tasks.
• Content manager training: how to log into admin panel, add products, upload images.
• Post-installation support for 30 days — consultations on settings.

Why Trust Professionals with Installation?

Incorrect installation means lost time and money. We've seen projects where a store on "Start" couldn't handle 50 visitors because innodb_buffer_pool_size wasn't configured. After migrating to VPS with correct configuration, the site "flew". Incorrect configuration can cost 30,000 RUB monthly due to excessive resource consumption. You get a ready-made architecture that scales. Order turnkey 1C-Bitrix installation — get a reliable platform for business growth. Contact us for a free consultation: we'll calculate the cost and time for your project. Over 7 years of experience, 120+ Bitrix projects implemented, including highload stores with million-item catalogs. Get in touch — we'll help configure Bitrix for your project.