Documentation

Web to app guide

A purchase in the native app can keep the website visitor. Pass that visitor id on the link that opens the app, then record events from your server. There is no React Native SDK in this package.

1. On the website, read ml_vid (or attribution().ml_visitor_id) after the tracker has loaded.
2. Open an https link on a host you control, with that id in the query string: https://example.com/open?vid=VISITOR_ID. vid is AnalyticFast's name for the parameter, not a platform requirement.
3. iOS: serve Associated Domains / universal links for that host so the link opens the app. Read the query from the user activity. Android: verified App Links, then Intent.getData() and the vid query parameter. Someone without the app stays on the website.
4. The app sends vid to your backend. Your backend, not the app binary, holds the API token and calls AnalyticFast.

await analytics.track({ name: 'app_open', visitorId: vid, eventId: `app_open:${vid}:${day}` });
await analytics.payment({
  transactionId: storeTransactionId,
  amountMinor: 2999,
  currency: 'USD',
  visitorId: vid,
});

Server events only attach to a visitor who already has a website session. A pure native install with no prior pageview is rejected (visitor_not_found) and does not create a visitor or a traffic source. The token stays out of the app. Universal links and App Links prove the host association; the vid query value is still just the id the website already stored in a first-party cookie.

Official references, checked 2026-10-26: Associated domains, universal links, Android App Links, incoming intent data.