Docs
Hostnames and subdomains
Allowed hostnames are whatever origins actually send events. The board does not invent hosts. localStorage visitor IDs do not cross subdomains.
Markdown · same page for crawlers. index, follow.
What the board shows
The Hostnames table lists hosts stored on events (from the page URL). Filter chips compose with channel, country, and the other row filters. Empty means no hostname on events in this range.
Same visitor only on one origin
localStorage.cashline_vid is scoped to scheme + host + port. www.example.com and app.example.com are different origins. They will not share a visitor_id. Zarstat does not set a cookie on .example.com to paper over that.
First-party script
Host /cashline.js on the origin you measure: copy public/cashline.js, or serve the file from your Zarstat deploy and point the script tag at that origin. Collect posts to the script origin. That keeps the request first-party for that origin. It does not merge IDs across subdomains.
There is no shared-subdomain proxy in this product. A reverse proxy that only rewrites /cashline.js and /api/collect onto one host still stores the visitor id on the page origin the browser is sitting on.
Next.js and GTM
App Router: load the script once in the root layout. GTM: one Custom HTML tag on All Pages. Details: Next.js · Google Tag Manager. Metrics definitions: board metrics.