Cross-domain tracking

When a visitor follows a link from example.com to app.example.io, MetricRaven can keep counting them as the same visitor, so the signup or payment on the app is credited to the campaign that brought them to the landing site.

Subdomains of one domain (www, app, shop) don't need this: they share the visitor through data-domain. Use cross-domain tracking for different root domains, like a marketing site and an app, a site and a separate store, or several brand domains.

Set it up

1. Add every domain to the site

   In Settings → General → Site, list all the domains under the same site. Visits are only accepted from these domains, and links are only joined when they come from one of them.

2. Install the same script on each domain

   Use the same site ID everywhere, and add data-allowed-hostnames with your other domains, comma-separated. Listing the current domain too is fine, so the same tag works on all of them.

   index.html

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   <!-- On example.com and on app.example.io: the same tag, listing the other domain(s). -->
   <script
     defer
     src="https://metricraven.com/js/script.js"
     data-site-id="YOUR_SITE_ID"
     data-allowed-hostnames="example.com,app.example.io"
   ></script>

3. Links and forms are handled for you

   When a visitor clicks a link or submits a form that leads to a listed domain (or one of its subdomains), the tracker adds a short mr_link parameter. The page that opens reads it, removes it from the address bar straight away and continues the visit.

Links you build in code

Navigation through window.location, window.open or a router doesn't go through a link click, so add the parameter yourself, right before navigating:

// Links and forms are linked automatically. For navigation in code, add the token first:
window.location.href = window.analytics.linkUrl("https://app.example.io/signup?plan=pro");

// Or append the parameters yourself (empty until the tracker has a fresh token):
const params = new URLSearchParams(window.analytics.linkParams());

With the npm package:

import { init, linkUrl, linkParams } from "@metricraven/web";

init({ siteId: "YOUR_SITE_ID", allowedHostnames: ["example.com", "app.example.io"] });

// Build the URL right before navigating: tokens expire after 30 minutes.
window.open(linkUrl("https://app.example.io/signup"), "_blank");
linkParams(); // { mr_link: "…" } or {}

linkUrl only changes URLs that lead to one of your listed domains, so it is safe to call on any URL. It returns the URL unchanged until the tracker has its first response. See NPM package.

Privacy model

No visitor ID ever appears in a URL. The parameter is an opaque token that only MetricRaven's server can read, and it is useless anywhere but in the browser it was made for.

Consent works the same as on a single domain:

• No consent on the receiving domain: nothing is stored in the browser there. The server remembers that this browser's daily ID on that domain belongs to the linked visitor until the end of the UTC day, the same lifetime as the daily ID itself, then forgets it.
• Consent on the receiving domain: the visit continues with the linked visitor's ID, as subdomains do with the shared cookie. If the visitor only had a daily ID on the first domain, today's visits from it join this domain's consented ID, just as visits from before consent do on one domain.
• Consent granted later on the receiving domain: the stored ID becomes the linked visitor's, so the journey stays in one piece.

See Consent & visitor IDs for how IDs work before and after consent. Deleting a person also deletes these same-day links.