Clarvivo

Free tool by Clarvivo · no login

Check where attribution resets across domains

Supply both sides of a real handoff—your site and checkout or hosted form—and see whether campaign parameters and click-ID persistence survive the boundary.

Starting URL

Supply both sides of the actual handoff. We open them in one isolated browser session and inspect campaign parameters and redacted attribution storage at the boundary.

This tool answers: Where do session and source identifiers reset across domains?

Enable JavaScript to run the check — the diagnosis itself is free and needs no account.

Why this happens

Many businesses run more than one domain: a marketing site and an app, a blog and a store, a main site and a checkout on a separate domain. Analytics treats each domain separately unless it's told otherwise, so when a visitor crosses from one to the other, the campaign that brought them is often left behind.

On the second domain the visit looks new, with the first domain as its referrer or as Direct. Conversions that happen there are credited to your own site rather than the campaign that started the journey. Paid channels look worse, self-referrals look like a top source, and nobody notices because each domain's reports look internally consistent.

This checker opens both sides of your real handoff in one browser session and shows whether campaign parameters, click IDs and attribution storage survive the crossing.

Next checks

These answer the questions this one tends to raise.

How this check works

So you can trust the result — and your developer can verify it.

  1. Paste both sides of the handoff

    The starting URL (with campaign parameters) and the destination on the other domain, as a visitor would reach it.

  2. We open them in one session

    Both pages are loaded in the same isolated browser so the journey behaves like a real visit.

  3. We compare identifiers at the boundary

    We check which UTMs and click IDs from the starting URL reach the destination URL, and list any that were lost.

  4. We check click-ID storage on the destination

    We look for Google click-ID storage (such as _gcl_aw) after the handoff, which shows whether Google's tags can still attribute the visit.

Common causes and fixes

Cross-domain measurement not configured
In GA4, add every domain to the cross-domain configuration so the linker parameter carries the session across.
Links that don't get decorated
Buttons that navigate with JavaScript, forms and redirects may not receive the linker parameter. Use real links or decorate the URL yourself.
Destination strips query parameters
If the destination redirects and drops the query string, the linker and campaign parameters are lost.
Own domains not excluded as referrals
Add your own domains to GA4's unwanted referrals so a crossing doesn't start a new session.

Frequently asked questions

What if both URLs are on the same domain?
Then there's no cross-domain boundary, and the result says so. Use the UTM Loss Detector for same-site journeys.
What is the _gl parameter?
Google's linker parameter, added to links between configured domains so the session and click information carry across.
Why do I see my own domain as a referral source?
Because visitors crossing between your domains start new sessions with your other domain as the referrer.
Does it test subdomains?
Subdomains of the same domain usually share cookies, but you can test them if attribution looks broken.
Is anything submitted?
No. The check only loads the two URLs.

See the journey that crosses your stack.

Clarvivo joins acquisition and payments even when the customer moves between systems.

Connect the full customer journey

What this tool reads, and what it keeps