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The new addition: under your website, or next to it?
You know how to decide, with a real criterion instead of a guess, whether the new addition to your business goes in a folder of your website or in a separate subdomain.
By Yodai · Published September 6, 2026 · Updated October 12, 2026
You have your website at yourdomain.com and it's up and running. Now you want to open an online store, launch an English version, or set up a new WhatsApp number for reservations. The question comes up right away: does that go under the website you already have, at yourdomain.com/store, or does it get set up separately, at store.yourdomain.com?
They sound almost the same, but they're not. One is an extra room in the same house. The other is a new house that happens to share your street name. Choosing wrong doesn't show up on day one. It shows up the day you want to switch providers, move the store, or open in another country, and you find out everything you built depends on a decision you made without thinking it through.
An extra room, or a new house
A folder is just another page on the website you already have: same domain, same engine, same security lock. If your website is yourdomain.com and you add /store, as far as any browser is concerned it's still the same website, just with one more door.
A subdomain is a different animal. store.yourdomain.com almost always points to a different engine, often on another server, with its own security certificate. It shares the name with your website, but not the house. It can even be managed by another company, with a different dashboard, without your original website ever knowing it exists.
- It separates easily from the rest of your site: it can live on another server, with another provider
- It needs its own DNS record and, almost always, its own security certificate
- It can run on a completely different engine than your website without stepping on it
- If you shut it down tomorrow or switch providers, it doesn't touch a single piece of the rest of your site
- People already visiting your site find it without leaving
- It lives inside the same engine and the same certificate as the rest of the website
Which to choose: Choose a folder when the new thing runs on the same engine you already use for your site: it's adding one more page, not setting up a separate business. Choose a subdomain when the new thing runs on a different engine (a catalog from another provider, a booking platform that isn't yours), because forcing it into a folder means forcing two engines to coexist where they don't fit.
The real test: which engine runs the new thing
The usual mistake is deciding based on how the name sounds. Store.yourdomain.com seems fancier and yourdomain.com/store seems more low-key, so people pick by taste. That's not the right test.
The question is which engine will run the new thing. If the store runs on the same engine you already use for your site (same account, same dashboard), then it's literally just one more page: it goes in a folder. But if the store runs on a different engine (a catalog from a wholesaler, a booking platform from a third party), that engine doesn't fit inside your folder. It needs its own subdomain, because it really is another engine running somewhere else.
Think of a hair salon that already has its website built on one engine, and now it wants to sell hair care products. If that same engine can also run a store, everything goes in /store: same account, same dashboard, one new button in the menu. But if the salon wants to use the catalog from the brand it carries, with its own search bar and its own cart, that's not really its own page. It's someone else's engine, and it belongs on a subdomain.
A new language isn't a different business
With language, the answer almost never changes. If you're translating the same content, the same store, and the same contact number, that goes in a folder (yourdomain.com/en), not a subdomain (en.yourdomain.com). It's the same site and the same engine: only the text changes.
The exception comes up when what you're opening isn't a language, it's a different market: another country, another currency, maybe another domain ending for that country. That decision carries more weight than a language choice and has its own rule, covered later in this course. Here, as long as you're translating the same business, a folder is the simplest to maintain: it stays on the same server as the rest.
What has nothing to do with the domain at all
Your new WhatsApp number doesn't hang off your domain: it lives on WhatsApp. There's no folder-or-subdomain decision to make, because it belongs to neither. A button on your homepage that opens that number is enough, or at most a short page in a folder (yourdomain.com/whatsapp) if you want to explain what that channel is for first, say, to separate reservations from complaints.
With that, you now have the full rule: a folder if the new thing runs on the same engine you already use, a subdomain if it runs on a different one. What comes next is making sure each new piece (the subdomain, the number, the payment button) proves it's really yours before anyone trusts it.
- A folder when the new thing runs on the same engine you already use for your website
- A subdomain when the new thing runs on a different engine and doesn't fit in your folder
- A new language for the same business goes in a folder. A different market is a separate decision
- Your WhatsApp number doesn't depend on the domain: all it needs is a button
Test yourself
Answer before opening each one. If one gives you trouble, go back to the section that explains it.
1. You built your website with one engine and want to sell the candles you make yourself, using that same engine for the catalog. Folder or subdomain?
Folder: it's the same engine and the same dashboard, so it's just one more page on the website you already have, not a separate business.
2. A sportswear wholesaler gives you access to their own catalog, with their own shopping cart, so you can resell their products. Where do you put it?
Subdomain: that catalog runs on the wholesaler's engine, not yours, and forcing it into your folder mixes two engines that don't play well together.
3. You want to translate your site into English because customers from abroad are starting to write to you, with the same catalog and the same prices. Folder or subdomain?
Folder, yourdomain.com/en: it's the same business and the same engine, only the text language changes. If tomorrow you also change prices or currency for another country, that's a separate decision.
If your new piece goes on a subdomain, keep in mind that the new DNS row doesn't copy what you've already set up on your main domain, and that's the first thing you'll want to check.
In Yodai you connect the domain you already have to your site, and it stays registered where it is, in your name. See how your own domain for your website works.
NextThe new subdomain doesn't inherit anything from the old setup