Do flat URLs really hinder Google's understanding?

What does a "flat" URL really mean according to Google?

A flat URL refers to a structure without a hierarchy of folders or clearly identifiable parameters. For example: mysite.com/room-paris-marais, where all elements are merged into a single segment. Google explains that this approach makes it difficult to identify what relates to the location (Paris), the type of property (room), or the district (Marais).

In contrast, a structured URL might look like mysite.com/rooms?city=paris&district=marais or mysite.com/paris/marais/rooms. In these cases, Google can isolate each component and test its impact by temporarily removing it during analysis.

Why does Google want to "test" by removing parameters?

The principle is simple: Google wants to understand which element of the URL carries semantic value. By successively removing parameters or segments, the engine observes if the content changes radically or remains coherent. This is particularly crucial for sites with multiple facets (e-commerce, directories, real estate sites).

If the URL includes ?city=paris&district=marais, Google can remove &district=marais and check if the page remains relevant for "Paris" in a broader sense. This ability to isolate variables helps avoid duplicate content and better understand the granularity of content. With a flat URL, it is impossible to perform this test — everything is blended into one inseparable block.

Does this statement contradict past recommendations on "SEO-friendly" URLs?

Not really, but it brings an important nuance. Google has always advocated for readable, short, and descriptive URLs. What Mueller emphasizes here is that "readability" is not enough — there also needs to be a programmatically analyzable structure. A URL can be perfectly understandable for a human and still opaque for a bot.

The debate between "folders vs parameters" is not settled. Both approaches can work, as long as there is a clear logic. The mistake would be to flatten everything thinking it gains simplicity. Let’s be honest: a short URL is worthless if Google cannot extract the relevant components from it.

• Hierarchical structure: facilitates the identification of depth levels and categories
• Explicit parameters: allow Google to test the removal of variables and evaluate their impact
• Flat URLs: problematic for sites with multiple facets (filters, locations, options)
• Consistency: choose one approach and stick to it across the entire site
• Testability: Google prefers structures that it can deconstruct and analyze by components

Is this statement consistent with real-world observations?

Yes, and it is even one of the rare times when Google provides a concrete insight into its analysis process. In the field, we do observe that sites with structured URLs (folders or parameters) often achieve a better contextual understanding of their pages. Real estate and e-commerce sites that have migrated to more explicit structures frequently report improved indexing of variants.

However — and this is where it gets tricky — Mueller does not say this directly impacts ranking. He talks about "understanding", not ranking. The correlation exists, but the causal link remains unclear. [To verify]: Does Google really adjust the relevance score based on this understanding, or does it simply optimize its crawl budget?

What is the limit of this recommendation?

The statement mainly applies to sites with high traffic volumes and multiple facets. For a typical blog or a showcase site with 50 pages, the impact will be marginal. The architecture of URLs becomes critical when managing thousands of pages with combinations of filters: city × type × price × availability.

Another point: Google mentions the ability to "test by removing", but does not provide any quantitative criteria. How many parameters is too many before it becomes counterproductive? What depth of folders is acceptable? No comment. We’re left with a qualitative recommendation that must be interpreted according to context.

Should flat URLs be completely avoided?

No. Some flat structures work very well if the content is sufficiently distinct and non-redundant. For example, URLs like /seo-technical-guide or /backlink-audit pose no problem — there’s nothing to deconstruct, each page is unique.

The problem arises with implicitly parameterized pages: /apartment-paris-2rooms-75m2-balcony. Here, Google cannot tell which criteria are essential. If you generate 10,000 URLs of this type, you create a nightmare for indexing. Better to structure it: /apartments/paris?rooms=2&area=75&balcony=yes.

Should all URLs of an existing site be restructured?

No, unless you notice massive indexing or cannibalization issues. A URL overhaul involves 301 redirects, a risk of temporary position loss, and significant technical work. Prioritize this action if your site generates thousands of similar pages with low semantic differentiation.

On the other hand, for a new project, integrate this logic from the design phase. Structure your URLs with a clear hierarchy or explicit parameters. Avoid merging everything into a single slug stuffed with keywords separated by hyphens.

How can I check if my current structure is a problem?

Analyze your Search Console: pages crawled but not indexed, pages discovered but not crawled, duplication of title/meta tags. If you see hundreds of nearly identical URL variants, it is a signal. Also, compare the number of indexed pages (site:mydomain.com) to the actual number of pages — a significant gap reveals confusion.

Use Screaming Frog or a similar crawler to map your URLs. Look for repetitive patterns. If you generate URLs like /product-red-size-M, /product-blue-size-M, /product-red-size-L without parameters, Google is likely to get confused.

What is the best approach for a complex site?

Favor a mixed structure: folders for the main hierarchy (categories, geographical areas), parameters for filters and options. For example: /real-estate/paris/apartments?rooms=2&price=500000. This allows Google to understand that Paris is a location, apartments a type, and the rest of the filters are optional.

Document your logic in an internal structure file. Define which parameters are essential (must generate an indexable page) and which are secondary (can remain noindex or canonical). This avoids anarchic proliferation of indexed URLs.

• Audit current URLs via Search Console and a crawler to identify problematic patterns
• For a new site, design a hierarchical structure (folders) or parameterized structure (query strings) from the start
• Avoid flat URLs with multiple criteria merged into a single slug
• Use explicit parameters for testable facets (color, size, price, location)
• Document URL logic in an internal guide to maintain consistency
• Test the impact with a sample before generalizing a massive overhaul