Site architecture

Architecture is one decision repeated: how does someone get from the homepage to the page that answers their question, and how does a crawler follow the same path. Depth, navigation, URLs, and internal links are four views of that one structure, so change them together or they drift.

Depth

Aim to put any page that matters within three clicks of the homepage. It isn't a law, but a critical page four or more levels down is a symptom worth chasing.

Shape	Fits	Costs
Flat, 2 levels	Small sites, portfolios	Stops scaling once a nav item has 20 children
Moderate, 3 levels	Most SaaS and content sites	Usually the right answer
Deep, 4 or more	Large catalogs, big docs	Scales, but buries things without strong linking

Go as flat as the navigation tolerates. When a dropdown passes roughly 20 items, that's the signal to add a level rather than keep the list flat.

Levels: L0 is the homepage, L1 is a primary section (/features, /blog), L2 is a page within it (/features/analytics), L3 and beyond are detail pages (/docs/api/authentication).

Site types as starting points

Type	Depth	Sections	URL shape
SaaS marketing	2 to 3	Home, Features, Pricing, Blog, Docs	/features/{name}, /blog/{slug}
Content site	2 to 3	Home, Blog, Categories, About	/blog/{slug}, /blog/category/{slug}
Ecommerce	3 to 4	Home, Categories, Products	/{category}/{subcategory}/{product}
Documentation	3 to 4	Home, Guides, Reference	/docs/{section}/{page}
SaaS plus content	3 to 4	Home, Product, Blog, Resources, Docs	/product/{feature}, /blog/{slug}
Small business	1 to 2	Home, Services, About, Contact	/services/{name}

URLs

Readable, lowercase, hyphenated, mirroring the hierarchy, with one trailing-slash policy enforced everywhere. Short but still descriptive: /blog/landing-page-conversions beats /blog/how-to-improve-your-landing-page-conversion-rates.

The mistakes that cost the most:

• Dates in blog URLs. /blog/2026/07/25/title adds nothing and ages the post visibly.
• IDs or query strings carrying content. /product/12345 and /blog?id=123 should be slugs.
• Over-nesting past what the hierarchy needs.
• Mixing parents for the same kind of page, like /features/analytics alongside /product/automation.
• Changing a URL without a 301. Every old URL needs one, or the links pointing at it stop counting and anyone who bookmarked it gets a 404. This is the single most common cause of traffic loss after a redesign.

references/patterns.md has the URL pattern per page type, navigation layouts, and the diagram formats to hand back.

Navigation

Primary navigation holds 4 to 7 items, ordered by importance, with the logo linking home and the call to action rightmost. Past 7, people stop reading the list and start hunting.

Footers group into columns: product, resources, company, legal. Sidebars carry within-section navigation for docs and long content. Breadcrumbs mirror the URL path exactly, with every segment linked except the current page, and they pair with BreadcrumbList schema.

Breadcrumbs are the cheapest structural win available: they add internal links on every page, they make hierarchy legible to a crawler, and they can earn a richer result.

Internal linking

• No orphans. Every page needs at least one internal link pointing at it, and the sitemap is not a link.
• Anchor text describes the destination. Never "click here" or "read more".
• How many contextual links a single page carries is a decision for whoever owns that page's format, so recommend the connections worth making rather than a density target.
• Link the pages that matter more often. Inbound internal links are how you tell a crawler what's important.
• Hub and spoke for content clusters: one comprehensive hub, spokes covering sub-topics, each spoke linking back to the hub, the hub linking to all spokes, and spokes cross-linking where a reader would actually want it.

Hub and spoke is what makes a set of posts add up to more than its pages, because it concentrates the signal on the hub rather than spreading it across a dozen equal posts competing with each other.

What to hand back

An ASCII tree of the hierarchy with the URL at each node, a URL map table (page, URL, parent, where it appears in navigation, priority), the redirect list when anything moves, and a Mermaid diagram when the structure is worth seeing rather than reading. references/patterns.md has the formats.

Sources

• Google Search Central, URL structure best practices: https://developers.google.com/search/docs/crawling-indexing/url-structure
• Google Search Central, Redirects and Google Search: https://developers.google.com/search/docs/crawling-indexing/301-redirects
• Google Search Central, Breadcrumb structured data: https://developers.google.com/search/docs/appearance/structured-data/breadcrumb
• Nielsen Norman Group, Flat vs deep website hierarchies: https://www.nngroup.com/articles/flat-vs-deep-hierarchy/