# Subdomain tracking (https://talivia.com/docs/subdomain-tracking)



Use one Talivia website ID and the same root `data-domain` on every subdomain:

```html
<script
  defer
  src="https://talivia.com/script.js"
  data-website-id="YOUR_WEBSITE_ID"
  data-domain="example.com"
></script>
```

This covers flows such as:

```text
example.com -> app.example.com -> checkout.example.com
```

If the website only runs on one hostname, this setup is optional: tracking works with a host-only cookie. Talivia Cloud includes `data-domain` in the generated snippet so a later move to subdomains does not silently split visitor identity.

Talivia stores an anonymous visitor cookie for 365 days and refreshes the shared session cookie for 30 minutes after activity. Tabs and subdomains therefore remain in one journey instead of creating separate visitors.

Use the registrable root domain (`example.com`). Do not set `data-domain="app.example.com"` when the visitor also moves through `example.com`.