YML Feed Generation for Yandex.Market: No Errors, Fast Updates

Recently a store with 30,000 products approached us: their feed was 20 MB, but on upload Yandex gave a price missing error for every second item. It turned out the price was stored in a separate table without an index, and the generator couldn't pull the cost in time. After implementing our solution, errors disappeared, and the feed started updating every 2 hours without downtime. We helped the client avoid fines and save time on manual export.

In this article we'll break down typical problems, generator architecture, and implementation steps. You'll learn how to avoid common mistakes and reduce feed maintenance time. We've prepared a checklist of typical issues to help with self-setup. If you encounter feed errors, contact us — we'll set up the generator in 2 days.

How to Avoid Common Errors When Exporting Products to YML Feed?

Typical errors: missing required fields, incorrect nesting, exceeding description length. Our generator automatically checks each field before writing. If price is missing or zero, the product is excluded from the feed to avoid penalty points. We also check categoryId for parent category existence and currency code validity. All errors are logged with product ID.

Problems We Solve — Product Export to YML Feed

• Incorrect prices and currencies — stores often indicate price without VAT or forget currencyId. Our generator automatically inserts RUR and checks that price is greater than zero.
• Feed too large — a catalog of 50,000 products weighs 25 MB. Without gzip Yandex may not accept. We add on-the-fly compression.
• Frequent updates — if prices change hourly, the feed should update just as often. We configure cron with intervals from 1 hour.

How We Do It

We use PHP and Laravel. For generation, the YmlFeedBuilder class based on XMLWriter. This allows forming the feed without loading the entire DOM into memory.

class YmlFeedBuilder { public function build(string $outputPath): void { $writer = new XMLWriter(); $writer->openUri($outputPath); $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')); $this->writeShopInfo($writer); $this->writeCurrencies($writer); $this->writeCategories($writer); $this->writeOffers($writer); $writer->endElement(); $writer->endDocument(); $writer->flush(); } private function writeOffers(XMLWriter $writer): void { $writer->startElement('offers'); Product::with(['category', 'attributes', 'images']) ->where('active', true) ->where('price', '>', 0) ->chunk(500, function ($products) use ($writer) { foreach ($products as $product) { $this->writeOffer($writer, $product); } }); $writer->endElement(); } } 

Using chunk() is mandatory — attempting to load 50,000+ products in one query leads to OOM. Our experience with catalogs from 500 to 500,000 products guarantees stable generation. We ensure compliance with the Yandex.Market format. Yandex.Market

Why Background YML Feed Generation Is Critical for Large Catalogs?

For catalogs over 10,000 products, on-the-fly generation is unsuitable — response time exceeds limits. We use a queue or cron task. The feed is written to disk or S3, then becomes available via a direct link. This avoids timeouts and reduces server load.

Performance Comparison

Generation via XMLWriter is 2x faster than via SimpleXML and consumes 30% less memory. This is critical for volumes over 50,000 items.

Offer Types and Their Features

Feed Validation

Before sending to Yandex.Market, the feed should be validated locally. Use the official Yandex.Market validator. Our generator includes built-in validation:

class YmlFeedValidator { public function validate(string $filePath): array { $errors = []; $dom = new DOMDocument(); if (!$dom->load($filePath)) { return ['XML parse error']; } $offers = $dom->getElementsByTagName('offer'); foreach ($offers as $offer) { $id = $offer->getAttribute('id'); if (!$offer->getElementsByTagName('price')->length) { $errors[] = "Offer {$id}: missing price"; } if (!$offer->getElementsByTagName('url')->length) { $errors[] = "Offer {$id}: missing url"; } // Check description length (Yandex truncates after 3000 characters) $desc = $offer->getElementsByTagName('description')->item(0); if ($desc && mb_strlen($desc->textContent) > 3000) { $errors[] = "Offer {$id}: description too long"; } } return $errors; } } 

Yandex.Market recommends not exceeding 500 MB per feed (per official documentation).

Update Schedule

• Prices and stock — change frequently: recommended regeneration every 1–4 hours.
• Attributes and descriptions — change slowly: once a day is enough.
• New products — immediately or at the next hourly cycle.

Example configuration in Laravel:

$schedule->job(new GenerateYmlFeedJob)->everyFourHours(); 

Feed Size Optimization

Yandex.Market recommends not exceeding 500 MB per feed. If the catalog is larger, split by categories and register multiple feeds.

Reduce size without quality loss:

• Exclude products without price (WHERE price > 0)
• Exclude inactive categories
• Truncate description to 1000–1500 characters
• Compress feed with gzip — Yandex supports it

Size comparison table:

How to Set Up a YML Feed Generator: Step-by-Step Guide

1. Create a YmlFeedBuilder class based on XMLWriter as shown above.
2. Configure product retrieval with query optimization (use chunk()).
3. Add validation of required fields before writing.
4. Implement update scheduling via cron or queue.
5. Enable gzip compression and check the feed with the official validator.

Implementation Timeline

• Basic generator with default type: 1–2 days
• Adding typed offers (vendor.model): +0.5 day
• Validator + error logging: +0.5 day
• Cron setup + public URL: +0.5 day

Total for a typical project: 2–3 business days. Price is calculated individually — savings on support and fines justify the investment.

What's Included

• YML feed generator tailored to your catalog
• Built-in validator with error report
• Update schedule configuration (cron or queue)
• gzip feed compression
• Documentation on format and maintenance
• Staff training on feed management

Order YML feed setup and forget about errors. Get a consultation for your project — contact us.

Checklist of Typical Errors

• [ ] Inactive products with price 0
• [ ] Missing url or price
• [ ] Description longer than 3000 characters
• [ ] Incorrect category (parentId does not exist)
• [ ] Feed larger than 500 MB