Campaign Microsite or a Subfolder on Your Main Site?

Should a campaign live on its own domain or your main site?

On your main site, in a subfolder, almost every time. A new domain starts with no history in Google, splits your reporting, and creates a migration you will have to run later. A subfolder inherits the trust your main site already has and needs no cleanup when the campaign ends.

We get asked this at the start of most launches. Someone has a campaign name, marketing wants it to feel like its own thing, and buying the domain costs twelve dollars. The decision looks small.

It is not small. It is the difference between a page that can rank in a month and a page that cannot rank for a year.

Why do teams want a separate domain in the first place?

Usually three reasons, and two of them are real. The campaign needs to feel distinct from the parent brand. The main site is slow to change because of approvals or a locked template. Or somebody read that an exact match domain helps with rankings, which stopped being true a long time ago.

The first two are genuine problems. They are just organisational problems wearing an SEO costume. A separate domain solves the approvals issue by routing around the team that was slowing you down, which works right up until the campaign succeeds and nobody owns the site.

The third reason deserves a plain answer. A keyword in your domain is not a ranking shortcut. You are trading measurable search equity for a small branding gain.

What does a new domain actually cost you in search?

Time, mostly. A new domain has no crawl history, no internal links pointing at it and no established signals. Your main site has all three. Google's own site move guidance shows how slowly this stuff settles, even when you are actively helping it along.

That documentation says "For medium-sized websites, it can take a few weeks or more for Google to gradually start showing the new URLs instead of the old ones (and for larger sites, even longer)." It also notes that "To consider a site move complete, Googlebot will have to visit every URL on your old and new site at least once."

Those quotes describe a move, not a launch, but the underlying mechanic is the same. Google has to find the pages, crawl them, and decide what they are worth. A subfolder skips most of that because Googlebot is already visiting your domain regularly and your existing pages can link straight to the new section.

Does Google treat subdomains and subfolders the same?

Roughly, but Google's own recommendation leans to subfolders where it states a preference. Its URL structure guidance recommends a country specific subdirectory with a generic top level domain for geotargeting, giving "Recommended (using a country-specific subdirectory with gTLD): https://example.com/de/" as the example.

That is guidance about multi regional sites rather than campaigns, so we would not stretch it further than it goes. But the pattern is consistent with what we see in practice. Keeping things on one hostname concentrates signals instead of spreading them.

The same page gives a smaller tip worth following on any campaign URL. Google recommends "using hyphens (-) instead of underscores (_) to separate words in your URLs, as it helps users and search engines better identify concepts in the URL." We covered the broader version of this question in our piece on choosing a subdomain or a subfolder.

What breaks in your reporting when you split domains?

Attribution, mostly, and it breaks quietly. A separate domain is a separate Search Console property, so your campaign queries no longer sit alongside your brand queries. Comparing them becomes a manual export job that someone stops doing by month three.

Search Console's own documentation explains the split. For URL prefix properties it says "If your site supports multiple protocols (http and https), you must add a separate property for each protocol. Similarly, if you support multiple subdomains...you must add a separate property for each subdomain." A domain property covers subdomains, but a different domain is simply a different site.

There is room to do this, to be fair. Google states "You can have up to 1,000 properties in your Search Console account." The limit is not the problem. The problem is that nobody looks at the eleventh property.

The same fragmentation hits your analytics, your cookie consent setup, and any cross domain tracking you now have to configure and maintain. None of it is hard. All of it is work you did not need.

When is a separate domain genuinely the right call?

When the thing is genuinely separate, or when it must not be associated with your brand. A distinct product with its own roadmap and buyers can justify its own domain. So can a research project, an industry benchmark or a community you want to outlive the company that started it.

Legal and regulatory reasons count too. So does an acquisition where two brands have to coexist while a decision gets made. In those cases you are not choosing a domain for a campaign, you are choosing a home for a business unit.

The test we use is duration. If the thing has an end date, put it in a subfolder. If it will outlive the campaign that created it and needs its own identity, a domain becomes defensible.

What if you already launched on a separate domain?

You can consolidate, and it is worth doing if the microsite earned anything. The mechanism is permanent redirects. Google's documentation states that "The 301 and 308 status codes mean that a page has permanently moved to a new location," and that a permanent redirect signals "that the redirect target should be canonical."

So the equity is not stranded. You map each microsite URL to its closest equivalent on the main site, redirect one to one rather than dumping everything on the homepage, and then wait. Google's guidance is honest about the wait, noting that "the visibility of your content in Search may fluctuate temporarily during the move. This is normal and a site's rankings will settle down over time."

Keep the old domain registered and the redirects live long after you think you need them. Links in old newsletters and slide decks do not expire. We wrote up the mechanics in our guide to handling redirects.

How do you set up a campaign subfolder properly?

Give it a clean path, a real template and a plan for what happens after. A path like /launch or /report reads well, stays short and survives being said out loud. Then design the section so it can look different from the rest of the site without being a separate site.

That last part is where the branding objection usually dissolves. A subfolder can have its own layout, its own colour treatment and its own navigation. It is a design decision, not a domain decision. Most teams asking for a microsite actually want a visual break, and you can give them that on the main domain.

Decide the ending up front. Will the page stay and become an evergreen resource, get merged into a product page, or be redirected. Writing that down at launch is the difference between a tidy site and one with fourteen orphaned campaign pages nobody will admit to. Our notes on running seasonal campaign pages go through this in more detail.

What about the brand argument?

It is the strongest argument for a microsite and still usually loses. The pitch is that a campaign needs its own world, and a subfolder makes it feel like an afterthought. We understand the instinct, because a great campaign does deserve to feel like an event.

But the audience does not experience your URL the way your team does. Visitors arrive from an email, an ad or a search result, land on a page, and judge the page. Almost nobody reads the path and thinks less of it.

Meanwhile the search cost is real and immediate. Trading a measurable disadvantage for a feeling your buyers will not notice is a bad trade, and it is the one being proposed.

What would we recommend by default?

Subfolder on the main domain, distinct design, clear path, documented ending. Reach for a separate domain only when the thing is a business unit rather than a campaign, or when a legal or brand separation requires it. That default will be right in most B2B situations.

It also keeps your options open. A subfolder that outgrows expectations can be moved to its own domain later with a proper migration. A microsite that quietly underperforms for a year cannot get those months back.

If you are planning a launch and weighing this up, or you have a microsite sitting on a domain nobody wants to own, we are happy to talk through the options with you. You can find us at phoenix.studio.