What Is a Data Layer?

Estimated Reading Time: 3 minutes

When you send website data to a vendor, your tag management system must source that data from somewhere. If there is no structured, centralized location for your data, that often means scraping the data from wherever it exists in the source code. This could be from the paragraph text, image file names, linked URLs, and all other kinds of messy locations.

However, scraping data from various places (known as DOM scraping when on the website page) is labor-intensive and has the potential to set your data collection initiatives up for failure down the road when something changes. A basic, structured data layer on your site (known to developers as a JSON) centralizes your data and gives your tag manager a single, secure source to use to gather information.

It’s vital for organizations to use data layers, but in order to do so, you must fully understand them. According to Google: “A data layer is a JavaScript object that is used to pass information from your website to your tag manager container. You can then use that information to populate variables and activate triggers in your tag configurations.”

For example, suppose you pull a product ID on a product detail page from an image file name into a tag manager variable using some fancy jQuery or Javascript expression. Then imagine that a developer from another part of the company is working on a project to rename all the image files from your site. If that developer makes a change without anyone on your team knowing, you will lose all product ID data for those pages from your tags. Using a JSON object is like fencing off your data with yellow tape because this data object is built and labeled for your team to use—no need to worry about someone accidentally removing or changing it.

When you rely on DOM scraping to get your data, you never know when someone might unwittingly pull the rug out from under you by making a change to your website or app. It requires very little understanding of any programming language and becomes much easier to maintain and review your data without constant developer support when you are using a JSON. Additionally, it’s easy for your developers to deploy quick fixes to your JSON since it is very clearly labeled in the page’s source.

Installing a structured data layer in the form of a JSON object is a simple and clean method for maintaining the data on your site and ensuring it’s always available when you need it. Although DOM scraping may seem like it is saving you time, as implementing a JSON can be time-consuming at first, it has the potential to cost you a lot more time down the road as your site and data availability changes. A JSON is like a high-interest investment in your future—the rewards will absolutely be greater than the cost.

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Written By

Sonny Hughes
June 16, 2021