What is a data layer?

The data layer is…

the behind-the-scenes structure that web sites and mobile apps tap into for timely and consistent visitor data.

Breaking it Down

The most common way to define the data layer is through the use of what is sometimes referred to as a Universal Data Object (UDO), which is written in the JavaScript programming language. The types of data contained in a data layer can be numerous and varied, consisting of things like e-commerce transaction information, web behavioral data, and mobile application usage. The graphic to the right shows a web channel broken down by components.

The Customer Experience Technology Stack

It’s a “layer” because it is a logical element of the technology stack that delivers the interactive customer experience on your web site or mobile app.


The application layer is comprised of any number of digital vendors that support the functionality of your site, such as live chat, analytics, personalization, display advertising and more.


The data layer, which sits in the middle, transfers visitor interaction data occurring at the experience layer to vendors at the application layer.


The experience layer is the most visible. It is where the user interacts and engages with the your web site or mobile app.

So What Does a Data Layer Actually Look Like?

Here’s a sample snippet of a data layer that might be found on an e-commerce page.

How Does Tag Management Fit into This Discussion?

One of the main functions of tag management is to easily map the data collected during the interactions on your web, mobile, and other digital channels to digital marketing vendors who need this data to provide a better customer experience. When a data layer is properly defined, tag management systems can easily ensure that a product name is conveyed to your web analytics provider in the same way it is to your affiliate tracking system.

Why Should You Care?

A well-constructed data layer can act as both a common dictionary for your supporting digital marketing applications and a unifying road map for how you want to communicate with your customers. Without a model for how to think about your customer interaction data, you cannot unite your applications around common definitions. The data layer represents the promise of omnichannel marketing that many digital marketers strive to achieve.