Track visitors across different domains

Track visitors seamlessly when they navigate between completely different root domains (e.g., from example.com to myapp.io).

When to use cross-domain tracking

Use cross-domain tracking when you have multiple websites with different root domains that you want to track as a single user journey:

• Marketing site on example.com and app on app.io
• Main site on mysite.com and store on shop-mysite.com
• Multiple brand domains that share users

Setting up cross-domain tracking

1. Go to your website settings in DataFast
2. In the General tab, scroll to "Additional domains"
3. Add the other domains you want to track (e.g., myapp.io)
4. Install the tracking script on all domains with the same website ID, the same data-domain attribute, and add the data-allowed-hostnames attribute with your additional domain(s):

<script
  defer
  data-website-id="667a82ed968954a0831e484" 
  data-domain="myapp.com"
  data-allowed-hostnames="myapp.io"
  src="https://datafa.st/js/script.js"
></script>

How it works

When users click a link to one of your allowed domains, DataFast automatically appends tracking parameters (_df_vid and _df_sid) to preserve their visitor and session IDs across domains.

The URL parameters are automatically cleaned from the browser address bar after being captured, keeping your URLs clean.