URL Structure and SEO: flat, categories, or dates, which should you choose?

The structure of a URL plays a major role in SEO and user experience. Simplicity, organization, or temporality: flat URLs, categories, and dates each offer different approaches. But beware: if poorly chosen, a structure can quickly become a technical obstacle. Let’s explore their advantages, limitations, and best practices.

Flat URLs: content first

Flat URLs (e.g., site.com/seo-article) place the content directly at the root of the site. No /category/, no /2025/01/: everything is simplified.
From an SEO perspective, this format highlights the article without relying on a fragile site hierarchy. Even if you change your category structure, your URLs remain stable: no risk of redirection cascades or 404 errors.
For extra robustness, you can add a unique identifier to the URL (e.g., site.com/seo-article-123.html): this way, even if the slug changes, the link remains valid and stable.

This format also aligns with Google Search Central’s guidelines, which recommend using descriptive, understandable URLs without opaque or dynamic identifiers. This allows you to combine readability for users with long-term technical stability.

Also read:

• How to properly create SEO-friendly links?
• Infinite scroll, pagination & SEO: how to combine them without killing your traffic?

Category-Based URLs: useful but risky

Category-based URLs (e.g., site.com/seo/url-structure) provide strong contextualization for both Google and users. They also make it easy to target entire sections of the site for marketing campaigns.

The problem? If you modify the hierarchy (merge or rename categories), each change can affect dozens or even hundreds of URLs.
The result: a cascade of permanent redirects, or worse, 404 errors if the migration is poorly managed. These issues are common and can seriously harm SEO performance.

From a marketing analytics perspective, many marketers like having categories in URLs because it lets them segment thematic performance easily. But a far more robust alternative is to use a datalayer configured in Google Analytics. This allows you to associate each piece of content with information such as its category, type, or tag.
The result: you retain the same level of analytical detail (if not more) without depending on a rigid, SEO-risky URL structure.

Dated URLs: depth that hurts

URLs with dates (e.g., site.com/2022/08/seo-article) are common on blogs. They reassure users about freshness at the time of publication. But they bring two main drawbacks:

• They age poorly: an article published 5 years ago looks outdated, even if it’s still relevant
• They create “deep” URLs with multiple slashes, which dilutes hierarchy and sometimes complicates crawling.

For evergreen content, it’s better to avoid dates in URLs and instead use metadata to indicate the last update.

Universal best practices

No matter the format, some rules are non-negotiable:

• Use clear, natural keywords
• Prefer hyphens over underscores
• Limit URL depth and length
• Avoid special characters and unnecessary parameters

At Enodo, thanks to our Butterfly CMS and Semantic content editor, we help clients build stable, high-performance URLs aligned with their SEO strategy.

.html or folder-style URLs: which to choose?

Beyond the question of structure (flat, category-based, or date-based), another common consideration is the URL ending format: finishing with .html or using a folder-style format (e.g. site.com/article/).
From an SEO perspective, Google treats both formats equally — what really matters is consistency and stability over time.

Personally, I tend to favor .html for individual content pages (articles, product sheets, guides…), as it conveys the idea of a static and permanent document. Conversely, I usually opt for the folder format when it comes to dynamic listings (categories, content feeds, pagination), where the page is expected to evolve regularly.

The key is to avoid inconsistent mixes (some pages with .html, others without) and to stick to a clear convention from the start. Ultimately, readability for users and stability for search engines should guide your choice more than the technical format itself.

Common mistakes to avoid

• Overloading with subfolders (site.com/cat/sub-cat/article): this makes the URL heavier and dilutes semantics
• Changing structure too often: every migration comes with an SEO cost (redirects, link equity loss)
• Confusing marketing with SEO: categories are useful for marketing, but they shouldn’t dictate URL structure.

When to choose which structure?

• Flat: recommended in most cases, especially for evergreen content. Stable, simple, effective
• Categories: useful if you need immediate thematic grouping, but handle with care
• Dates: relevant for news, but best avoided for reference content

In short

• Flat URLs: stable, SEO-friendly, ideal for avoiding redirects and 404s
• Categories: convenient but risky if the structure changes
• Dates: useful for news but harmful in the long run
• .html for individual content, folder format for listings: pick a clear convention and stick to it

My recommendation: prioritize flat URLs with slug + unique ID to combine readability and robustness.