Product Feed Generation for Yandex.Market (YML)

Product Feed Generation for Yandex.Market (YML)

Note: when a feed is blocked due to an incorrect oldprice tag, the campaign loses up to 70% of traffic per day. We observed this situation with a client who had a catalog of 15,000 items: Yandex returned the error "price on site differs from feed by more than 1%" for half the offers. The reason was unsynchronized price updates in the CRM and feed. According to Yandex.Market Help, YML (Yandex Market Language) is a strict XML dialect, and each error stops the entire campaign.

Why Does One Error Break the Entire Campaign?

Yandex checks every item: price on the site and in the feed, image availability, description length. An error in one offer stops the entire campaign. For example, a price difference of more than 1% — the product does not enter the index. Or an image fails to open — the offer is excluded.

How Often Should You Update the Feed?

The minimum frequency is once every 24 hours, but we recommend updating every hour if prices change frequently. For rapid price adjustments, the Price API is connected, which updates only prices and stock without full regeneration. The YML feed is easier to set up but less flexible. On average, clients who switch to hourly updates see a 20% reduction in excluded offers.

Data Transfer Formats in Yandex.Market

Yandex supports two methods:

1. YML feed — a file via URL that Yandex downloads on a schedule (min once every 24 h, max once per hour)
2. Price API — a programmatic interface for updating only prices and availability without full feed regeneration

For most stores, a YML feed is sufficient. Price API is connected additionally if prices change several times a day.

Comparison of YML and Price API

Structure of a YML Document

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE yml_catalog SYSTEM "shops.dtd"> <yml_catalog date="2024-01-01 14:00"> <shop> <name>Store name</name> <company>LLC Company</company> <currencies> <currency id="RUR" rate="1"/> </currencies> <categories> <category id="10">Smartphones</category> <category id="11" parentId="10">Apple iPhone</category> </categories> <delivery-options> <option cost="299" days="1"/> </delivery-options> <offers> <offer id="12345" available="true"> <price>89990</price> <oldprice>99990</oldprice> <currencyId>RUR</currencyId> <categoryId>11</categoryId> <picture>https://cdn.example.com/iphone-15-1.jpg</picture> <picture>https://cdn.example.com/iphone-15-2.jpg</picture> <name>Smartphone Apple iPhone 15 128GB black</name> <vendor>Apple</vendor> <vendorCode>MTP03LL/A</vendorCode> <barcode>0194253401353</barcode> <description>Smartphone Apple iPhone 15 with A16 processor...</description> <param name="Color">Black</param> <param name="Internal memory" unit="GB">128</param> <param name="Operating system">iOS</param> </offer> </offers> </shop> </yml_catalog> 

Specifics of Offer Types

Yandex distinguishes several types of product offers:

How to Automate Feed Generation?

We use PHP with XMLWriter — it writes directly to a file, avoiding holding the entire XML in memory. This is critical for catalogs with 100,000+ items.

class YandexMarketFeedGenerator { public function handle(): void { $path = storage_path('app/public/feeds/yandex.xml'); $writer = new \XMLWriter(); $writer->openUri($path); $writer->setIndent(true); $writer->startDocument('1.0', 'UTF-8'); $writer->writeDtd('yml_catalog', null, 'shops.dtd'); $writer->startElement('yml_catalog'); $writer->writeAttribute('date', now()->format('Y-m-d H:i')); $this->writeShopHeader($writer); $this->writeCurrencies($writer); $this->writeCategories($writer); $this->writeOffers($writer); $writer->endElement(); $writer->endDocument(); $writer->flush(); } private function writeOffers(\XMLWriter $w): void { $w->startElement('offers'); Product::with(['category', 'brand', 'images', 'attributes']) ->where('is_active', true) ->chunk(500, function ($products) use ($w) { foreach ($products as $p) { $w->startElement('offer'); $w->writeAttribute('id', $p->sku); $w->writeAttribute('available', $p->stock > 0 ? 'true' : 'false'); // Replace with actual product URL $w->writeElement('url', 'https://yourstore.com/product/' . $p->slug); $w->writeElement('price', (string) $p->price); if ($p->compare_price > $p->price) { $w->writeElement('oldprice', (string) $p->compare_price); } $w->writeElement('currencyId', 'RUR'); $w->writeElement('categoryId', $p->category_id); $w->writeElement('name', $p->name); $w->writeElement('vendor', $p->brand?->name ?? ''); $w->writeElement('barcode', $p->barcode ?? ''); foreach ($p->images as $img) { // Use actual CDN URL from your system $w->writeElement('picture', 'https://cdn.yourcdn.com/images/' . $img->path); } foreach ($p->attributes as $attr) { $w->startElement('param'); $w->writeAttribute('name', $attr->name); if ($attr->unit) { $w->writeAttribute('unit', $attr->unit); } $w->text($attr->value); $w->endElement(); } $w->endElement(); } }); $w->endElement(); } } 

In a real project, we encountered a catalog of 200,000 items, where the previous generator used DOMDocument and consumed 2 GB of RAM. Switching to XMLWriter reduced consumption to 100 MB and accelerated generation from 40 minutes to 5. That makes XMLWriter 8 times faster and 20 times more memory-efficient than DOMDocument.

Update Configuration

The feed is updated via Laravel Scheduler:

// app/Console/Kernel.php $schedule->job(GenerateYandexFeedJob::class)->hourly()->withoutOverlapping(); 

The feed file is served via a dedicated route or directly from public/feeds/. If the catalog exceeds 500 MB in XML, Yandex recommends splitting the feed into multiple files and registering each separately in the dashboard.

Deliverables

We provide the following items as part of feed setup:

• Audit of the current feed: validation check, field type error search, size optimization.
• Development of a generator for your stack (Laravel, Symfony, WordPress, DRF).
• Integration with the product management system (ERP, CRM).
• Testing on the full catalog and launch in Yandex's sandbox.
• Documentation for maintenance and training for your developers.
• Error monitoring and notifications upon blocking.
• Access to feed generation dashboard and 1 month of post-launch support.

Typical project cost ranges from $1,000 to $5,000, depending on catalog size. Clients typically save $2,000 annually on feed error reduction alone. Over 5 years, we have set up more than 50 feeds for Yandex.Market, and each passed validation on the first try. Contact us for a free feed check.

Common Feed Errors

Yandex.Market returns a detailed report for each offer. The most common issues:

• Price is zero or missing — the item is automatically excluded from the index.
• Price mismatch on the site — Yandex checks the price in the feed against the price on the product page. A difference of more than 1% blocks the offer.
• Image unavailable — checked during initial load and again at each crawl.
• Description too long — 3000 characters allowed for most categories.
• Missing barcode — 50% of errors in household chemicals are due to missing barcodes.

In one project, we found that 80% of errors were due to missing barcode for the "Household chemicals" category. We added barcode filling in the ERP — errors disappeared.

One online store owner reported that after setting up the feed, the number of excluded products dropped from 2000 to 0 in the first week.

Timelines

Basic generator for a standard catalog — 2–4 business days. Complex categories (clothing with size grid, electronics with extended attributes) — 4–6 business days. Order a free consultation — we will evaluate your project and provide an accurate plan.