• I have a blog.

  • I have products on my page that I sell through a third-party service (that allows me to include analytics and trigger events if I want to).

Now, I would like to know how many visitors from the blog end up buying a product on my third-party service. Note that the blog will not link any product page (third-party service page) directly.

What I need is a way to "track" users and know if a visitor in my blog 30 days ago ended up purchasing the product today.

  • My blog links to the page (same domain).
  • The page has links to products (external).
  • Those product pages are hosted on a third-party service. (where I can integrate analytics using autoLink with my domain)


  • How do I do this?
  • Is it possible with Google Analytics?
  • How does this third party service attribute sales back to your blog? Commented Oct 26, 2021 at 11:01
  • 1
    I can integrate Google Analytics into it. So anything that can be done on a normal page can also be done here. How? That's what I'm asking :)
    – Steve
    Commented Oct 26, 2021 at 11:07
  • Right, but if users don't click from your site to buy the product, how does this third party site know that your blog was the one that referred them? Commented Oct 26, 2021 at 11:08
  • 1
    Blog links to the page (same domain). The page has links to products (external). Those product pages are hosted on a third-party service. (where I can integrate analytics using autoLink with my domain)
    – Steve
    Commented Oct 26, 2021 at 11:12
  • 1
    That's what I'm trying to figure out with this question.
    – Steve
    Commented Oct 26, 2021 at 12:37

1 Answer 1


Disclaimer: I have no idea how this works in GA4

Cross-domain measurement allows GA to track sessions across two domains as a single session. This is most commonly used for this exact reason: sites that use 3rd party e-commerce/shopping cart services.

By default, GA collects a Client-ID value on every hit, which get stored in cookies, but it's on a per-domain basis...and obviously 2 different sites cant just access each-other's cookies. So we have to transfer the Client-ID value from domain A to domain B.

You need to modify your tracking snippets for this, here's an example:

On Domain A (You):


(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||
[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })

ga('create', 'UA-XXXXXXX-Y', 'auto', {'allowLinker': true}); // set linker
ga('require', 'linker'); // require linker
ga('linker:autoLink', ['domain-b.com'] ); // add 3rd party domain
ga('send', 'pageview');


On Domain B: (3rd Party):

ga('create', 'UA-XXXXXXX-Y', 'auto', {'allowLinker': true});
ga('require', 'linker');
ga('linker:autoLink', ['domain-a.com'] );
ga('send', 'pageview');

Per your comment, I'm assuming your 3rd party service has some way of adding this.

Count it as 1 session vs 2

In order to measure the traffic as a single session tho you'll have to create a referral exclusion list in GA:

Hit Admin and then go to:

Property > Tracking Info > Referral Exclusion List > Add Referral Exclusion

Add your domains there.

Set up your goal

You'll want to configure a funnel goal to track when someone begins at your blog and ends up at your products.

Google Analytics Goal Funnel Example

Making it clear on reports

You might want to add a filter so that you can see different domains in your behavior/user journey reports instead of just page paths it's like that by default.

Filter Type: Custom filter > Advanced
Field A --> Extract A: Hostname = (.*)
Field B --> Extract B: Request URI = (.*)
Output To --> Constructor: Request URI = $A1$B1

Here's a nice article that goes much more in depth on the whole "how it works", and also provides instructions with Tag Manager.

  • The Cross-domain measurement is done by the third-party service. Nothing to worry about there. Regarding the goal part, I'm not sure if that'd really solve my problem. Will that also count users who visited the blog 30 days ago, and today they decided to make the purchase without passing through the blog again?
    – Steve
    Commented Oct 27, 2021 at 23:09
  • @Steve If you're running an attribution model other than last click you can modify your conversion lookback window up to 90 days. Commented Oct 28, 2021 at 0:17
  • So the answer is "by using Google Analytics Attribution"? :)
    – Steve
    Commented Oct 28, 2021 at 11:54

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