> For the complete documentation index, see [llms.txt](https://docs.jentis.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.jentis.com/data-capture/web-tracking-setup/set-up-gtm-data-layer.md).

# Set up GTM Data Layer

Use GTM window\.dataLayer events in JENTIS without custom code.

## Set up GTM Data Layer

### Introduction

JENTIS natively supports Google Tag Manager's `window.dataLayer`. You no longer need custom code to connect an existing GTM data layer to your JENTIS container.

Keep the data layer implementation already running on your website. Select the GTM data layer vendor, then configure mappings through the JENTIS interface.

A GTM data layer contains objects pushed by your website as visitors interact with it. These objects include an event name and related properties, such as product, cart, transaction, or value data.

JENTIS provides default mappings for standard GTM page view and ecommerce formats. This helps you start tracking quickly with the default GTM ecommerce model.

Customize the mappings when your implementation uses custom event names or properties.

### Before you begin

Your website must already push events to `window.dataLayer`.

{% hint style="info" %}
Remember to remove any custom code or states that translate your dataLayer into JENTIS States or \_jts.push()-calls if you activate the nativly supported data layer mapping. So your mapping is not applied redundantly.
{% endhint %}

JENTIS supports the default GTM ecommerce tracking model. Custom event structures can also be mapped.

### Next steps

Read on to learn how to configure GTM data layer mappings for your container. The following sections describe how to map events and properties in detail.


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