Microsites vs Subdomeinen vs Submappen: SEO-impact
Where you put your content — blog.company.com vs company.com/blog vs companyblog.com — has a direct impact on how Google ranks it. This isn't theoretical. Multiple large-scale studies (Moz, Ahrefs, SEMrush) have shown that subfolders consistently outperform subdomains and microsites for content that should share domain authority.
Yet companies keep spinning up subdomains for blogs, microsites for campaigns, and separate domains for products. The decision is usually made by marketing ("we want a separate brand") or engineering ("it's easier to deploy separately") without consulting SEO. The cost is invisible until six months later when the blog isn't ranking and nobody knows why.
How Google Treats Domain Authority
Google's official position: subdomains and subfolders are treated "mostly the same." In practice, the data tells a different story.
Subfolders inherit domain authority directly. Content at company.com/blog/article benefits from every backlink pointed at company.com. The authority flows within the domain. A high-authority homepage at DA 60 lifts every subfolder page.
Subdomains are treated as semi-separate entities. Google maintains separate crawl queues and can assign different authority signals to subdomains. blog.company.com doesn't automatically inherit the full authority of company.com. Links pointing to the main domain don't fully transfer to subdomains. John Mueller from Google has acknowledged this distinction, noting that Google needs to "learn to crawl them separately" and may treat them as separate sites in some contexts.
Microsites (separate domains) are entirely separate. companyblog.com has zero authority inheritance from company.com. It starts from scratch — no domain authority, no backlink benefit, no crawl history. Every link you build to the microsite benefits only the microsite.
The empirical evidence from a 2024 Ahrefs study of 10,000 sites:
| Structure | Average Organic Traffic (relative) | Time to Rank (new content) |
|---|---|---|
Subfolder (/blog/) |
100% (baseline) | 2-4 weeks |
Subdomain (blog.) |
65% | 4-8 weeks |
| Microsite (separate domain) | 25% | 8-16 weeks |
The 35% traffic gap between subfolder and subdomain content is massive for a B2B company depending on organic lead generation.
When Microsites Make Sense
Despite the SEO disadvantage, microsites have legitimate use cases:
Brand separation. When a product or service needs to be perceived as independent from the parent brand. Example: Google doesn't run YouTube at google.com/youtube. The brand identity, audience, and content strategy are different enough to warrant complete separation. If your microsite audience wouldn't benefit from association with your parent brand, a separate domain is justified.
Acquisitions. You acquired a company with existing domain authority and brand recognition. Redirecting their domain to a subfolder on your site destroys their brand equity and potentially their backlink value (if the content drastically changes). Keep the acquired domain alive, but plan a gradual migration if the brands are merging.
Campaign sites with a different risk profile. A viral marketing campaign, a controversial research publication, or a community-generated content platform might carry reputational risks you don't want associated with your primary domain. Isolation is protection.
Regulatory or legal requirements. Some industries require separate disclosures, terms, or regulatory filings that must be on a distinct domain. Financial services, healthcare, and gambling are common examples.
The test: would this content benefit from being associated with our primary domain? If yes → subfolder. If association actively hurts one or both brands → microsite.
The Subfolder Advantage
For nearly every B2B content strategy, subfolders win. The advantages stack:
Consolidated domain authority. Every backlink to any page on your domain strengthens every other page. A blog post that earns 50 backlinks lifts the authority of your services pages, your homepage, and every other blog post. With a subdomain, those 50 backlinks only help the subdomain.
Shared crawl budget. Google allocates a crawl budget per domain. Subfolders share the main domain's generous budget. A new subfolder page on a DA 60 domain gets crawled within hours. A new page on a fresh subdomain might wait days — Google allocates a smaller initial budget to subdomains it hasn't crawled extensively.
Internal linking power. Links from your blog to your services page pass maximum authority within a subfolder structure. Cross-subdomain links (blog.company.com → company.com/services) pass less authority, similar to external links.
Simpler analytics. One Google Analytics property, one Search Console property, one domain to monitor. Subdomains require separate Search Console verifications and complicate cross-domain tracking. Microsites need entirely separate analytics configurations.
Easier maintenance. One SSL certificate, one deployment pipeline, one set of headers and security configurations. Each subdomain or microsite multiplies your infrastructure maintenance.
The migration we do most often at Empirium: consolidating scattered subdomains into a subfolder architecture. A typical project involves moving blog.company.com to company.com/blog, docs.company.com to company.com/docs, and shop.company.com to company.com/shop. The SEO improvement typically shows within 4-8 weeks: 20-40% increase in organic traffic to the migrated content.
Subdomain Use Cases
Subdomains are the right choice in specific technical and organizational scenarios:
Application vs marketing site. app.company.com for the product (React SPA, authentication, user data) and company.com for the marketing site (static, public, SEO-optimized). These serve different purposes, different audiences, and different performance requirements. The marketing site needs to be fast, cacheable, and crawlable. The app needs authentication, real-time data, and client-side rendering. Forcing both into one subfolder architecture creates architectural compromises.
Separate technology stacks. Your marketing site is Next.js. Your documentation site is Docusaurus. Your API reference is Redocly. Running three different frameworks under one domain via path-based routing (nginx proxy) is possible but fragile. Subdomains simplify deployment: each subdomain has its own build, its own hosting, and its own deployment pipeline.
Geographic targeting (ccTLD alternative). If you can't use country-code TLDs (.de, .fr, .jp), subdomains like de.company.com or jp.company.com can signal geographic relevance to Google. This is less effective than ccTLDs or subfolder-based targeting (company.com/de/), but it's an option when organizational constraints prevent other approaches.
Isolation for security or compliance. User-generated content, third-party integrations, or untrusted code should be sandboxed on a separate origin (subdomain) to prevent XSS and cookie access to the main domain. This is a security requirement, not an SEO choice.
The URL structure decision matrix:
| Scenario | Recommended Structure | Why |
|---|---|---|
| Company blog | company.com/blog/ |
Authority consolidation |
| Documentation | company.com/docs/ or docs.company.com |
Depends on tech stack |
| Product app | app.company.com |
Different tech, auth required |
| Country-specific content | company.com/de/, company.com/fr/ |
Best SEO approach |
| Campaign landing pages | company.com/campaigns/name/ |
Authority inheritance |
| Acquired brand | Keep separate domain initially | Preserve existing authority |
| Community/forum | community.company.com |
UGC isolation |
FAQ
How do I migrate from a subdomain to a subfolder?
Set up the subfolder with all content replicated. Implement 301 redirects from every subdomain URL to its subfolder equivalent (blog.company.com/article → company.com/blog/article). Submit the new sitemap to Search Console. Monitor crawl errors for 4-6 weeks. Keep the subdomain redirects permanent — removing them will break existing backlinks. Expect a 1-2 week ranking fluctuation followed by gradual improvement.
Does Google Search Console data differ for subdomains vs subfolders?
Yes. Subdomains require separate Search Console properties. blog.company.com won't appear in the company.com property's data. You can add a domain-level property (DNS verification) that captures all subdomains, but individual subdomain performance is still reported separately. Subfolders share a single property — all data is consolidated.
What about www vs non-www?
www.company.com is technically a subdomain, but Google treats it as equivalent to company.com (it's the one exception). Pick one and 301 redirect the other. The choice doesn't matter for SEO — consistency does.
Should my international site use subdomains or subfolders?
Subfolders (company.com/fr/, company.com/de/) with hreflang tags. This is the consensus recommendation from every major SEO platform and Google's own documentation. Subfolders consolidate authority, simplify management, and are the easiest to implement correctly. Subdomains (fr.company.com) work but split authority. Separate ccTLDs (company.fr) are ideal for country targeting but expensive and complex to maintain.
Can I use both subfolders and subdomains on the same domain?
Yes, and many sites do. A common setup: company.com/blog/ (subfolder, SEO content), company.com/services/ (subfolder, marketing), app.company.com (subdomain, product), docs.company.com (subdomain, technical documentation). The key is putting SEO-critical content in subfolders and using subdomains only for technically separate applications.