Comparison · Infrastructure
Subdirectories vs subdomains vs separate domains for languages
A multilingual website needs a separate URL for each language version. There are three common structures: subdirectories on one domain (example.az/en/), subdomains (en.example.az) and separate domains (example.az, example.com). All can work with correct hreflang setup. They differ in how authority is shared, how complex maintenance is and how strongly each version is tied to a country.
[ 01 ]
In short
In short
- 01
Subdirectories keep all versions on one domain, sharing authority; simplest to manage — the usual recommendation.
- 02
Subdomains separate versions technically; search engines may treat them more independently.
- 03
Separate domains give strong country signals and brand separation, with the most maintenance.
- 04
URL parameters for language (
?lang=en) are not recommended. - 05
Whatever the structure,
hreflang, sitemaps and a correct language switcher are required.
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Comparison
Side by side
| Criterion | Subdirectories | Subdomains | Separate domains |
|---|---|---|---|
| Example | example.az/en/ | en.example.az | example.com |
| Shared authority | Yes | Partly | No |
| Setup and hosting | One site | Can be separate | Separate sites |
| Maintenance | Easiest | Moderate | Most effort |
| Country targeting | Via content and signals | Via content and signals | Strong with country domains |
| Analytics | One property | Cross-domain setup | Several properties or cross-domain |
| Brand separation | Low | Medium | High |
When subdirectories fit
- One brand and one organisation serving several language audiences.
- A team that manages all versions together.
- The goal of concentrating search authority.
This is the most common setup for businesses in Azerbaijan with Azerbaijani, Russian and English versions. See multilingual URL structure.
When subdomains fit
- Language versions run on different platforms or by different teams.
- Technical separation is needed, for example different hosting.
When separate domains fit
- Distinct country markets with different offers, prices and legal entities.
- Strong local brand presence in each country.
- Enough resources to build authority for each domain.
See .az domain vs .com.
Requirements for all options
- A separate URL per language for each page.
- Reciprocal
hreflangannotations with self-references andx-default. - Alternates declared only for real translations.
- A language switcher that keeps the user on the equivalent page.
- No automatic language redirects for search engine crawlers.
Verdict
For most businesses, subdirectories are the simplest and strongest option. Choose subdomains for technical separation and separate domains for truly separate country businesses.
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FAQ
Frequently asked questions
Should the main language have a prefix too?
Either way works: the main language at the root and others with prefixes, or every language with a prefix. Be consistent.
Do subdomains lose SEO value?
They are not penalised, but authority built on one subdomain benefits others less than within one domain.
Can we change the structure later?
Yes, with redirects for every URL and updated hreflang. It is a migration; plan it carefully.