Running multiple domains and subdomains on one account

A Measurebase domain subscription is really a root domain plus a subdomain you choose for the tagging server itself — the default suggestion is mbase, e.g. mbase.acme.nl, but you can pick anything. Once you understand that, adding a second property, a subsidiary brand, or a separate GTM container for the same site is just a matter of adding another subdomain.

Your own domain, or a Measurebase-generated one

When you add a domain, you choose between two paths. Use my own domain is the default and the one we recommend — you point a DNS record you control at Measurebase, and you get the full first-party tagging benefits: better cookie lifetime, less ad-blocker interference. Use a Measurebase subdomain skips DNS entirely — a subdomain is generated for you automatically — but since it isn't on your own domain, you lose those same first-party advantages. It's there for quick testing, or for the rare case where you genuinely can't set up DNS, not as a long-term substitute for your own domain.

The DNS record

For your own domain, domain settings shows one A record to add. An A record makes the tagging subdomain genuinely first-party: Safari's tracking prevention detects subdomains that alias a third-party service via CNAME and caps their cookies at 7 days, and an A record avoids that classification entirely — so measurement cookies keep their full lifetime.

Add the record, then use Verify DNS to check it's resolved — SSL is issued automatically once it has, no separate certificate step required.

Adding a second GTM setup on the same root domain

If you need a separate property, a subsidiary brand, or just a second, independent GTM container on a domain you've already added — create a new domain subscription for the same root domain and give it a different subdomain. Each subdomain runs its own, completely independent tagging server; nothing about the first one changes.

How many domains can you add?

That depends on your plan: the Free and Solo plans cover 1 domain, Growth includes 3, Scale 5 and Business 10. Anything beyond 10 domains is an Enterprise conversation. If you're at your plan's limit, adding another domain prompts you to upgrade rather than silently failing — the same limit is enforced on the backend too, not just as a dashboard nicety, so it's consistent everywhere you might try to add one.