URL structure: subfolder, subdomain, country domain.

On a multilingual site the language versions can be served under three different address structures, and the choice is the architectural decision hardest to reverse.

This decision is made at the very start, and changing it later is the most expensive: when the address structure changes, the accumulated indexing, link value and user bookmarks are all affected. Even with redirects in place, some loss occurs.

There are three options and none is right in every case. The choice depends on the team’s capacity and on how much the markets genuinely diverge.

The three options

1. Subfolder — language folders under a single domain. The one domain’s authority is shared, setup is easiest, maintenance cheapest.
2. Subdomain — each language at a separate subaddress. The separation is clear, but authority can split and separate configuration is needed.
3. Country domain — a separate domain per country. The strongest local signal, the highest cost and the most scattered authority.

For small and mid-sized sites the answer is almost always the subfolder. The reason is authority: the trust accumulating on a single domain spreads to all languages, whereas three separate domains mean building three separate authorities from zero.

A country domain makes sense only for genuinely diverging operations: a different legal entity, different pricing, different legal obligations, a different warehouse. Without those conditions, its cost does not pay off.

Should the slug be localized

Once the address structure is chosen, a second question follows: will the path segments be translated? That is, will the services page carry the same slug in every language, or that language’s own term?

The benefit of localizing is plain: the address bar carries the term searched for in that language, meaningful to user and search engine alike. The cost is plain too: a separate slug decision per language, and changing that slug later is a redirect debt.

On this site the slugs are localized: the services page carries three different paths in three languages. The decision is conscious — it raises the translation load but puts each language’s own term into the address.

1. Localized slug — each language’s own term. Better matching, more maintenance.
2. Shared slug — the same in all languages. Easy to maintain, weak to match.
3. Mixed — top-level paths translated, deep pages shared. A practical balance.
4. ID-based — the path carries a meaningless identifier. Easiest to maintain, weakest signal.

The third option is common on large sites and strikes a reasonable balance: categories are translated, individual product or article slugs stay shared. The maintenance load is kept bounded while the most-searched paths are localized.

How to decide

When choosing among the three options, the questions to ask are operational, not technical. As the answers clarify, the options narrow on their own.

1. Do the markets genuinely diverge — different pricing, stock, legal entity, legal obligations?
2. What is the team’s capacity — who will carry the configuration of three separate domains?
3. What is the authority situation — starting from zero, or is there a domain with accumulation?
4. What is the budget — country domains mean purchase, renewal and certificate costs alike.
5. Is the local signal critical — the country domain is the strongest signal but not sufficient alone.
6. Is there a way back — if this decision is changed later, what is lost?

The third item decides the matter alone in most cases: if a domain with accumulated authority exists, splitting it is almost always wrong. The subfolder structure spreads that accumulation to all languages.

The sixth item is a discipline question: if the decision’s rationale is not written down, someone joining the team a year later questions it and the debate starts over. Recording the rationale is as valuable as the decision itself.

Splitting a domain with accumulated authority is almost always the wrong decision.

Which language gets the root

When the subfolder structure is chosen, a second question follows: which language will the root address show? There are three options.

1. One language at the root, the others in folders — the most common. The root language holds a privileged position.
2. Every language in a folder, the root redirects — more symmetric, but a redirect cost at the root.
3. The root as a language-selection page — neutral but adds friction.

The first option is applied on this site: Turkish at the root, English and German in subfolders. The rationale is a market decision — the target audience is Türkiye-based, and the root address speaks to that audience directly.

The second option has an advantage: because the languages are symmetric, none looks privileged over another, and if the root language is to be changed later, no restructuring is needed. The price is that the root’s redirect adds a hop to every visit.

The decision leans toward the second option for a multinational brand and toward the first for a single-market business. And the real question to ask while deciding is this: does this site have a primary language, or are the languages equal?

A warning to close: this decision is presented as a technical preference, but it is really an operations decision. “Which structure is better” has no universal answer; “which can our team sustain” has a clear one. Asking the second question yields results faster than spending hours on the first.

A final technical note: whatever structure is chosen, the addresses need to be consistent. Addresses ending with a slash in one language and not in another; uppercase in one, lowercase in another — these produce a duplicate-content risk.

On this site all addresses end with a slash and all are lowercase. The slashless or index-file variants are redirected to the single form — measured live, they consolidate with a 307.

A record-keeping suggestion to close: the chosen structure and its rationale should be written into a decision log. That keeps someone joining the team a year later from reopening the same debate — and when the decision is to be changed, it recalls what was accepted as the price.