Cross-domain and subdomain tracking

Track several domains or subdomains as one site or as separate sites, keep visits together without cookies, and stop your own domain showing as a referrer.

# Cross-domain and subdomain tracking

> Track several domains or subdomains as one site or as separate sites, keep visits together without cookies, and stop your own domain showing as a referrer.

## One site, several hostnames

Add every hostname under **Site settings → General → Additional
domains**. Subdomains of a listed domain (`www.`, `shop.`, `docs.`) are
accepted automatically. Then choose under **Multiple domains**:

- **Combined** (default): the visit key doesn't include the hostname, so a
  visitor moving from `example.com` to `shop.example.com` (or to
  `example-checkout.com`) the same day continues the **same visit**, and
  links between them are internal, not referrals.
- **Separate**: the hostname is part of the visit key, so each domain has
  its own visits, as if they were separate sites that share a dashboard.
  Use the **Hostnames** tab of the Pages panel to compare them.

In combined mode no cookies or link decoration are needed to join visits
across domains: visits come from the daily visit key, which is the same on
every domain of the site. A visit continues only while the visitor keeps
the same IP address and browser, with gaps under 30 minutes.

## Your own domain shows up as a referrer

If `example-checkout.com` appears as a referrer on `example.com`, it isn't
one of the site's domains. Add it as an additional domain, and it becomes
internal for new visits. Subdomains of the site's domains are already
internal.

## Separate sites instead

Create separate sites when the properties have different owners, goals or
privacy settings. Visitors moving between them then show the other site as
a referrer, as for any external site.

## Staging and preview domains

Hits from hostnames that aren't the site's domains are dropped, so
staging (`*.vercel.app`, `*.netlify.app`, `staging.example.com`) doesn't
pollute production data. If staging is a subdomain of your domain, it is
accepted, so exclude it: list only your production hostnames in
`data-domains` (exact hostnames, so include `www.` if you use it), or add
a hostname [traffic rule](/docs/privacy/traffic-rules).

Visualizza come Markdown

One site, several hostnames#

Add every hostname under Site settings → General → Additional domains. Subdomains of a listed domain (www., shop., docs.) are accepted automatically. Then choose under Multiple domains:

Combined (default): the visit key doesn't include the hostname, so a visitor moving from example.com to shop.example.com (or to example-checkout.com) the same day continues the same visit, and links between them are internal, not referrals.
Separate: the hostname is part of the visit key, so each domain has its own visits, as if they were separate sites that share a dashboard. Use the Hostnames tab of the Pages panel to compare them.

In combined mode no cookies or link decoration are needed to join visits across domains: visits come from the daily visit key, which is the same on every domain of the site. A visit continues only while the visitor keeps the same IP address and browser, with gaps under 30 minutes.

Your own domain shows up as a referrer#

If example-checkout.com appears as a referrer on example.com, it isn't one of the site's domains. Add it as an additional domain, and it becomes internal for new visits. Subdomains of the site's domains are already internal.

Separate sites instead#

Create separate sites when the properties have different owners, goals or privacy settings. Visitors moving between them then show the other site as a referrer, as for any external site.

Staging and preview domains#

Hits from hostnames that aren't the site's domains are dropped, so staging (*.vercel.app, *.netlify.app, staging.example.com) doesn't pollute production data. If staging is a subdomain of your domain, it is accepted, so exclude it: list only your production hostnames in data-domains (exact hostnames, so include www. if you use it), or add a hostname traffic rule.