Your product feed is the foundation of every Google Shopping campaign. It determines which searches your products appear for, how they're displayed, and whether they're eligible to show at all. With Shopping ads now appearing on new surfaces like Google's AI Mode, feed quality affects even more placements than before. Yet most advertisers treat their feed as a one-time setup task rather than an ongoing optimization lever.
According to Google's product data specification, the data you provide directly affects ad quality and relevance. A well-optimized feed improves impression share, click-through rates, and conversion rates—all without increasing your ad spend. This guide covers which attributes matter most, how to optimize each one, and where to focus your effort for maximum impact.
How Google Evaluates Your Feed
Google evaluates your product feed on two levels: eligibility and competitiveness. Understanding this distinction is key to prioritizing your optimization work.
Eligibility: The minimum bar
Eligibility determines whether your product can show at all. Missing required attributes, policy violations, or data mismatches between your feed and landing page will get products disapproved. This is binary—your product either shows or it doesn't.
Competitiveness: How well you rank
Once eligible, your product competes against other merchants for the same search queries. Google uses your feed data—titles, descriptions, images, product identifiers, and category mapping—to determine relevance. Better data means better matching, higher quality scores, and more favorable ad placement.
Think of it this way: eligibility is the door, competitiveness is the race. Most advertisers focus only on getting through the door and ignore the race entirely.
Key Insight
Google's algorithm weighs feed quality signals alongside bid and budget. Two products with identical bids but different feed quality will perform differently. Optimizing your feed is effectively free performance improvement.
Required vs Optional Attributes
Google's Merchant Center requires a set of core attributes for every product. But the optional attributes are where competitive advantage lives.
Required attributes
| Attribute | Impact Beyond Eligibility |
|---|---|
| title | Primary matching signal for search queries. Front-load keywords. See our product title optimization guide for formulas by category. |
| description | Secondary matching signal. Include relevant keywords naturally within the first 500 characters. |
| image_link | Directly affects CTR. High-quality images on white backgrounds outperform low-resolution alternatives. |
| price | Competitiveness signal. Google factors price into ad ranking for commercial queries. |
| availability | Must match landing page. Mismatches trigger disapprovals and erode account health. |
| brand | Matching signal for branded searches. Enables brand filtering in Shopping results. |
| condition | Filters product in relevant contexts (new vs refurbished). |
High-impact optional attributes
| Attribute | Why It Matters |
|---|---|
| gtin | Enables product catalog matching and richer listings. Products with GTINs typically get more impressions. |
| google_product_category | Helps Google classify your product correctly. Auto-assignment is often inaccurate for niche products. |
| additional_image_link | Multiple angles increase buyer confidence. Google may show different images in different contexts. |
| product_type | Your own category hierarchy for campaign organization. See product type vs category. |
| color, size, material | Enable filtered searches. Required for apparel; strongly recommended for all categories. |
| sale_price | Triggers sale annotations in Shopping results, which improve CTR. |
| custom_label_0–4 | Enable campaign segmentation by margin, season, performance tier, or any custom logic. |
Image Optimization
Product images are the first thing shoppers notice in Shopping results. A poor image kills click-through rates regardless of how good your title, price, or product is. Google is also increasingly strict about image quality—violations can trigger disapprovals.
Resolution and format
The minimum is 100×100 pixels for non-apparel and 250×250 for apparel, but aim for at least 800×800. Higher resolution images display better across devices and Shopping surfaces like the Shopping tab and Google Images. Maximum file size is 16 MB. Supported formats include JPEG, PNG, GIF, BMP, TIFF, and WebP.
White backgrounds vs lifestyle
For non-apparel products, use a clean white or neutral background with the product filling 75–90% of the frame. This is what Google recommends and what performs best in Shopping results. For apparel, lifestyle images showing the product on a model tend to outperform flat-lay or mannequin shots.
Multiple images
Use additional_image_link to provide up to 10 additional images per product. Include different angles, close-ups of important details, and in-context usage shots. Google may select different images for different placements.
Common Image Mistakes
Promotional text overlays ("SALE", "FREE SHIPPING"), watermarks, and logos on product images are policy violations that will get products disapproved. Use clean product photography and let Google's native sale annotations handle promotions.
Description Best Practices
Product descriptions serve as a secondary matching signal. Google uses them alongside titles to understand what your product is and match it to relevant searches.
What to include
- Key features and specifications: Material, dimensions, compatibility, technical specs
- Use cases: Who the product is for and how it's used
- Differentiators: What makes this product different from alternatives
- Relevant keywords: Natural variations of search terms people use
What to avoid
- Promotional language ("best price", "buy now", "limited time")
- Excessive capitalization or special characters
- Competitor brand names (unless it's a genuine compatibility reference)
- Duplicate content copied from manufacturer descriptions without any customization
Character limits and placement
Descriptions can be up to 5,000 characters, but front-load the most important information in the first 150–500 characters. Google truncates descriptions in most Shopping placements, so the beginning matters most.
GTINs & Product Identifiers
Product identifiers (GTIN, MPN, brand) enable Google to match your products to its global product catalog. This matching unlocks richer product data, better search matching, and participation in features like product reviews and price comparisons.
Why GTINs matter
- Catalog matching: Links your product to Google's global database with enriched data
- Better matching: Products with GTINs are more accurately matched to search queries
- Richer listings: Enables product ratings, reviews, and comparison features
- Competitive data: Enables the price competitiveness report for benchmarking
When to use identifier_exists = false
Set identifier_exists to false only when your product genuinely doesn't have a GTIN, MPN, or brand. This applies to:
- Custom-made or handmade products
- Vintage items and one-of-a-kind pieces
- Store-brand products without assigned GTINs
- Product bundles you've created yourself
Important
If a GTIN exists for your product but you don't provide it, Google may limit your product's visibility. Don't use identifier_exists = false as a shortcut to avoid looking up identifiers. According to Google's full automation guidelines, accurate identifiers are essential for catalog-level optimization.
Supplemental Feeds & Feed Rules
Your primary feed is the source of truth, but Merchant Center offers two mechanisms to enhance it without modifying the source: feed rules and supplemental feeds.
Feed rules
Feed rules are transformations applied inside Merchant Center. They let you modify attribute values using operations like set, extract, prepend, and append. Use feed rules when you need to:
- Prepend brand names to product titles automatically
- Set default values for missing attributes (like shipping or condition)
- Extract color or size information from titles or descriptions
- Map your product types to Google's taxonomy categories
Supplemental feeds
Supplemental feeds are separate data files that add or override attributes on your primary feed, matched by product ID. As explained in DataFeedWatch's feed types overview, they're ideal for:
- Adding custom labels for campaign segmentation without changing your e-commerce platform
- Overriding titles with manually optimized versions for top products
- Adding missing GTINs from a separate database or spreadsheet
- Fixing sale prices or promotional data for specific products
When to use each
Feed rules work best for systematic transformations that apply across many products. Supplemental feeds work best for targeted overrides on specific products. Many merchants use both: feed rules for broad cleanup, supplemental feeds for strategic optimization of top performers.
Optimization Priority Framework
Not all feed optimizations deliver equal return. Here's where to focus based on impact and effort, as recommended by feed optimization research:
Priority 1: Fix eligibility issues first
- Resolve all disapprovals and errors in Merchant Center diagnostics
- Ensure price and availability match between feed and landing pages
- Add missing required attributes
Priority 2: Optimize titles
- Restructure titles to front-load the most relevant keywords
- Follow category-specific formulas (Brand + Product Type + Key Attributes)
- Use the full 150-character limit to include more matching signals
Priority 3: Add missing identifiers and images
- Add GTINs to every product that has one
- Upload additional product images for top sellers
- Ensure all images meet quality standards
Priority 4: Enrich optional attributes
- Add color, size, material, and pattern for all applicable products
- Set up custom labels for campaign segmentation
- Add google_product_category for products where auto-classification is wrong
Priority 5: Ongoing maintenance
- Audit feed quality monthly
- A/B test title structures on top products
- Update supplemental feeds as product catalog changes
Key Takeaway
Focus on titles and identifiers first—they deliver the biggest performance improvement relative to effort. Attribute enrichment and supplemental feeds come next. Tools like SKU Analyzer help you identify which products have feed issues alongside their performance data, so you can prioritize fixes on products that actually get traffic.
Frequently Asked Questions
What is the most important product feed attribute for Google Shopping?
Product title is the single most impactful attribute. Google uses your title to match products to search queries. A well-structured title with brand, product type, and key attributes (color, size, material) directly affects which searches your products appear for and your click-through rate.
Do I need GTINs for Google Shopping?
GTINs are strongly recommended but not always required. Products with GTINs get matched to Google's product catalog, which enables richer listings. If your product doesn't have a GTIN (custom or handmade items), set identifier_exists to false. However, if a GTIN exists for your product, not providing it can limit performance.
What is a supplemental feed and when should I use one?
A supplemental feed is an additional data source that enriches your primary feed by adding or overriding attributes matched by product ID. Use supplemental feeds to add custom labels, override titles, add missing GTINs, or fix data without modifying your primary feed source. They cannot create new products—only enrich existing ones.
What image resolution does Google Shopping require?
The minimum is 100×100 pixels for non-apparel and 250×250 for apparel. Google recommends at least 800×800 pixels. Higher resolution displays better across devices. Maximum file size is 16 MB, and supported formats include JPEG, PNG, GIF, BMP, TIFF, and WebP.
How often should I update my product feed?
At least once daily. Price and availability changes should be reflected within 24 hours to avoid mismatches. For high-velocity inventory, use the Content API for real-time updates. Google allows up to four scheduled fetches per day.
Start Optimizing Your Feed Today
Feed optimization is the highest-leverage, lowest-cost improvement you can make to your Google Shopping campaigns. Unlike bid changes or budget increases, feed improvements compound over time—better data leads to better matching, which leads to better performance across every product in your catalog.
Start with eligibility: fix disapprovals and data mismatches. Then move to competitiveness: optimize titles, add identifiers, improve images. Use supplemental feeds and feed rules to make changes without disrupting your primary data source.
SKU Analyzer connects your Merchant Center feed data with Google Ads performance metrics, so you can see which products have feed quality issues alongside their revenue, ROAS, and impression share. Instead of optimizing your feed blind, you can prioritize the products that matter most.