How do you allow customer enter their own google anlytics tracking / measurement id on any domain?

Question

Consider a SAAS provider offering landing pages for user. The pages are hosted under the provider's domain: https://landingpagesinc.com/myname

Now lets consider the provider wants to allow users add their GA tracking ID i.e. G-XXXXXX.

How does the provider facilitate this ?

Do they simply add the GA SDK with the user provided tracking id ? If so, does Google do any domain whitelisting ? If they don't, anyone could add any measurement ID to any website. If they do, then how come these providers do the tracking on behalf of the user as the tracking is coming from the provider's domain and not the user's domain ?

Answer 1

Besides Google, there are many other vendors to conduct tracking. Even if it's just Google, there are multiple ways to deploy tracking.

What a normal landing page SAAS would have to do is allow the clients to deploy any kind of custom JS onto the landings. Whether it's tracking or not is not important. I would definitely not touch a landing that would not allow that. The ability to properly measure the efficiency of ad campaigns by deploying pixels is critical for marketing. That implies the need for free eval. or a tag management system like GTM, which is essentially the same but in GUI.

Some less agile SAASes, especially the web3.0ish b2b solutions would often allow partners enter their GTM ids and then deploy their GTMs on the pages for them. An example would be say Cirque Du Soleil wanting to sell tickets from some generic local ticket aggregator. The aggregator will allow them to make their own landings within the aggregator's site and allow them deploy their GTM there to conduct the tracking as they see fit. Usually it is expected that an aggregator like this would also provide some essential dataLayer events for GTM to hook into.

When the SAAS has no trust in their clients' competency, which is common for b2c SAASes, then yes, they would typically limit the tracking options to asking the clients for their measurement id. That's very primitive though. That's probably Etsy's or Amazon's level unless they provide their own analytics instead. The trouble with GTM is that it has the power of eval. Direct GA implementations are way more limited, but they don't give the power of eval to the customers. Obviously, it's more important to Etsy or Amazon to maintain their brand image than to give the sellers the power to analyze. Eval would have allowed them to do nearly anything to their landings.

Another example is Unbounce. Unbounce doesn't really care if the customer breaks a landing since the customer pays for it. They don't lose anything from that, so they allow custom JS or GTM on their landings. Same can be said about the web3.0 paid hostings like shopify. Deploy away.

Yes, google tracking scripts don't do intentional whitelisting by domain. However, hostname is one of the dimensions that are normally automatically tracked, so it becomes a trivial task to filter out unwanted domains from particular reports. Still, even if the customer doesn't want to mix their first-party data with some vendor's data, it's free to create as many GA properties as one needs and generate new measurement ids for vendors.

When you create a web property in GA, you're prompted to set the domain, but that's mostly to be able to make paths clickable from reports. And yes, it will be a bit messy when there's more than one domain sending the data. But everyone got used to that.