Online store catalog structure

Catalog structure is how products are arranged into categories, subcategories, filters and page URLs. It answers two questions: can a customer find what they need in a few clicks, and does a search engine understand which pages matter.

Why it matters right now

Baymard Institute evaluates the navigation of top stores every year. In its "Homepage and Category Navigation UX 2026" study (over 17,000 ratings from 180+ US and European sites; article updated October 13, 2026), category taxonomy turned out to be the weakest topic on both desktop and mobile: 61% of sites on desktop and 65% on mobile were rated "mediocre" or "poor" (Baymard). So this is a typical problem, not a rarity, and good structure gives a real advantage.

There is no Ukrainian data of this scale for 2025-2026, so below the Baymard studies show shopper behavior in the US and Europe, and the Google documentation shows the rules for search.

Step 1. Start with how customers search

Structure is built not around the warehouse or 1C, but around the customer's language.

1. Collect queries from Google Search Console, your internal site search, Keyword Planner and conversations with support.
2. Group them by purpose, not by manufacturer: "running shoes", not "Nike".
3. Test with two or three people from outside the team: ask them to find a specific product and watch where they click. A short overview of the method is in usability.

Example (a made-up cosmetics store). The warehouse stores goods by brand. A customer searches for "vitamin C serum" or "cream for dry skin". Categories by product type and skin concern will be more useful than an alphabetical list of brands, and the brand is better made a filter.

Step 2. Separate categories and filters

The most common mistake according to Baymard: 79% of sites use separate categories where they should offer filters for product types with shared attributes. The study's recommendation: if products share attributes, show them in one list with a filter, so the customer can see the whole range (Baymard).

A practical rule:

• A category answers "what kind of product is this".
• A filter answers "which exactly": color, size, brand, price, material, availability.

In the clothing example, "T-shirts" and "Shirts" are categories, while "men's", "cotton" and "size M" are filters. More on filters is in the article product filters.

Step 3. Keep depth and breadth within limits

From the same Baymard data:

• 51% of sites do not break categories and subcategories into convenient chunks.
• Recommendation: split a category into subcategories when it holds about 10 items, and aim for at least 10 products in the deepest category. More than about 10 subcategory options overloads users.

This is not a law of nature but an empirical guideline from tests. If a category has two products, it does not need a page of its own; if it has 3,000 items, it needs subcategories and filters.

Step 4. Show customers where they are

Baymard records that 96% of sites do not highlight the current section in the main menu (it was 95% in 2025), 31% do not make menu headings clickable, and 22% do not put product categories at the first level of the mobile menu. Recommendations: on mobile, show product categories at the first level, highlight the current section, make parent categories clickable, and on intermediate pages put subcategories at the top, above promo blocks, with clear thumbnails (38% do not do this, and 39% have unclear or missing thumbnails) (Baymard).

For hover dropdown menus the study advises a delay of 300-500 ms so the menu does not fire by accident. Mobile has no hover, so the priority there is simple first levels. See mobile UX and the category page.

Step 5. Breadcrumbs

Breadcrumbs show the path to a product and help the user go up a level. Google uses `BreadcrumbList` markup to show this path in search results and advises showing the typical user path rather than copying the URL structure. If a product is reachable by several paths, you can specify several trails (Google Search Central).

Step 6. Page addresses (URLs)

For search engines, structure is also URLs. What Google recommends for online stores (Google Search Central):

• Each product variant (color, size) can have its own URL, but the main product URL stays canonical, pointed to by `rel="canonical"`.
• Use descriptive words in the URL, not numbers: `/product/black-t-shirt` is better than `/product/3243`.
• Write parameters as `key=value` (`?page=2`, `?color=green`) and do not repeat the same parameter.
• Do not use `#` fragments to show different content, because Google ignores them.
• Each pagination page has its own URL; be consistent about the first page (always with `?page=1` or always without).
• Do not link empty categories in the menu: close an empty page with `noindex` or return 404.
• Use `<a href>` links rather than JavaScript navigation, and give meaningful link text (the product name, not "read more").
• Use the same URL in links, the sitemap and canonical.

Step 7. Filters and search indexing

If filters build URLs through parameters, the number of pages can become almost endless, and Google's crawlers waste their resources. Google's documentation (Search Central) offers a choice:

• Filtered URLs are not needed in search: block them in `robots.txt` (example: `/?color=`) or pass filters after `#`; product pages and the category without filters stay open.
• Needed in search (for example, "red sneakers"): use the standard `&` separator, keep the filter order in the URL fixed, and return 404 for combinations with no results. Google warns that this increases server load and slows discovery of new URLs.
• Google treats `rel="canonical"` and `nofollow` as weaker signals: canonical may reduce crawling over time, and `nofollow` works only if every link to such a URL is marked with it.

A practical approach: make filter pages that match popular queries separate landing pages with a unique title and text, and close the rest.

Step 8. The data the structure rests on

• Attributes. Name the same characteristics the same way across the whole catalog, otherwise filters fall apart. For a large range, a PIM does this.
• Categories in analytics. In Google Analytics, the "Ecommerce purchases" report passes the product category in five levels (`Item category` to `Item category 5`) (Google Analytics Help). If your catalog is deeper, the data will need simplifying, so plan for it in advance.
• The feed. Categories in the product feed for Google or marketplaces must match their classification, not only yours.
• Merchandising. The order of products in a category is a separate job (merchandising).

How to rebuild a live catalog

1. Take current data: which categories bring traffic and orders, which are empty or duplicated.
2. Draw the new structure and map every old URL to a new one.
3. Redirect old URLs to new ones with a permanent server redirect (301/308), not to the homepage. The rules are in the article migrating to a new platform.
4. Update the sitemap, canonical and internal links.
5. After 2-4 weeks, compare traffic by category and search queries.

Common mistakes

• Building categories around internal accounting rather than customer queries.
• Making a category out of what should be a filter (color, brand).
• Creating empty and duplicate categories.
• Giving filters endless URLs without indexing rules.
• Forgetting the mobile menu: product categories should be the first level.

FAQ

How many levels of nesting should a catalog have? There is no hard number. Baymard's guideline is to subdivide a category at about 10 items and have at least 10 products in the deepest category. Depth should be such that the customer does not get lost.

How is a category different from a filter? A category answers "what is it", a filter answers "which exactly". Products with shared attributes are better shown in one list with a filter.

Do colors and sizes need separate URLs? Google allows a separate URL for a variant (via path or parameter), but advises making the main product URL canonical.

How do I keep filters out of the index? Through `robots.txt` for filter parameters, or by passing filters in the URL fragment. Canonical and nofollow are weaker.

Related terms

• Category page
• Catalog filters
• Product variants
• PIM system
• Site search
• How to move to a new online store platform without losing traffic and data

Sources

• Baymard Institute, Homepage and Category Navigation UX 2026: 10 Pitfalls and Best Practices (оновлено 13.10.2026) — baymard.com/blog/ecommerce-navigation-best-practice
• Google Search Central, Designing a URL structure for ecommerce sites — developers.google.com/search/docs/specialty/ecommerce/designing-a-url-structure-for-ecommerce-sites
• Google Search Central, Managing crawling of faceted navigation URLs — developers.google.com/search/docs/crawling-indexing/crawling-managing-faceted-navigation
• Google Search Central, Breadcrumb structured data — developers.google.com/search/docs/appearance/structured-data/breadcrumb
• Google Analytics Help, Ecommerce purchases report — support.google.com/analytics/answer/12924131