A subdomain creates a distinct hostname such as shop.example.co.uk, while a subdirectory keeps content under the main host, such as example.co.uk/shop/. Choose based on operational separation and user needs, not on a claim that one structure automatically ranks better.
Practical comparison
| Criterion | Subdomain | Subdirectory |
|---|---|---|
| Infrastructure | Can use a separate platform or server | Usually shares the main site platform |
| DNS and certificate work | Requires hostname records and certificate coverage | No separate DNS record for the section |
| Access control | Can be administered independently | Usually tied to the main application |
| Analytics and search setup | May need additional configuration and review | Often easier to keep in one reporting structure |
| User experience | Can feel like a separate product | Usually feels like part of one website |
Use a subdirectory when
- The content belongs to the same audience and editorial system.
- Navigation and design should remain unified.
- The main platform can support the functionality safely.
- There is no strong operational reason for a separate host.
Use a subdomain when
- A service requires a separate platform or security boundary.
- A customer portal, documentation system or shop is operated independently.
- Different teams need separate deployment and access controls.
- The hostname will remain a distinct, maintained product rather than a temporary workaround.
Plan the technical details
A subdomain needs DNS, HTTPS coverage, monitoring and possibly separate Search Console or analytics configuration. A subdirectory may require reverse proxying or application integration if it is served by another system. Neither option is automatically simple.
Avoid unnecessary migrations
Moving established content between a subdomain and subdirectory changes URLs. Use one-to-one redirects, update internal links, canonicals and sitemaps, and monitor the move. Do not restructure solely to chase an assumed SEO preference.
Examples
A blog written by the same editorial team normally fits naturally at /blog/. A hosted customer portal with separate authentication may be safer at portal.example.co.uk. Documentation maintained in a specialist system can use either structure, depending on whether the business can integrate it reliably under the main path.
Do not let a vendor’s technical limitation silently determine the information architecture. Record why the structure was chosen and what migration would be required if the vendor changes.
Final publication check
- The structure follows an operational need, not an SEO myth.
- A subdomain has DNS, HTTPS, monitoring and ownership.
- A subdirectory is technically supportable by the chosen platform.
- Any migration includes one-to-one redirects and updated internal signals.
Sources and date checked
Technical and policy information was checked on 21 July 2026. Recheck provider-specific procedures before making a live change.
Keep the decision under your control
Retain the relevant accounts, source material, supplier terms and recovery information. Recheck changing prices, interfaces and rules before acting.