Build a comprehensive data layer for WordPress including WooCommerce, page builders, and custom content

WordPress Data Layer for GTM

Learn how to structure and populate the GTM data layer with WordPress-specific data for advanced tracking and personalization.

Understanding the Data Layer

The data layer is a JavaScript object that passes information from WordPress to Google Tag Manager (and other tools). It acts as a bridge between your CMS and your tags.

Benefits of a Proper Data Layer

Decouples tracking from presentation - change templates without breaking tags
Enables advanced personalization - target users based on WP data
Simplifies tag management - tags pull from consistent variables
Improves debugging - centralized data source for troubleshooting

Data Layer Structure

dataLayer = [{
    // Page metadata
    'pageType': 'blog-post',
    'pageName': 'How to Use WordPress',
    'pageCategory': 'Tutorials',

    // User information
    'userStatus': 'logged-in',
    'userRole': 'subscriber',

    // Content attributes
    'postID': '123',
    'postAuthor': 'John Doe',
    'publishDate': '2024-01-15'
}];

Basic WordPress Data Layer

Initialize Data Layer Before GTM

Always initialize the data layer before GTM loads:

add_action('wp_head', 'initialize_data_layer', 0); // Priority 0 runs first
function initialize_data_layer() {
    ?>
    <script>
        window.dataLayer = window.dataLayer || [];
    </script>
    <?php
}

add_action('wp_head', 'populate_wordpress_data_layer', 1);
function populate_wordpress_data_layer() {
    // Gather WordPress data
    $page_type = 'unknown';
    if (is_front_page()) {
        $page_type = 'homepage';
    } elseif (is_single()) {
        $page_type = 'blog-post';
    } elseif (is_page()) {
        $page_type = 'page';
    } elseif (is_archive()) {
        $page_type = 'archive';
    } elseif (is_search()) {
        $page_type = 'search-results';
    } elseif (is_404()) {
        $page_type = 'error-404';
    }

    // User status
    $user_status = is_user_logged_in() ? 'logged-in' : 'logged-out';
    $user_role = 'guest';
    if (is_user_logged_in()) {
        $user = wp_get_current_user();
        $user_role = !empty($user->roles) ? $user->roles[0] : 'subscriber';
    }

    // Build data layer
    $data_layer = array(
        'pageType' => $page_type,
        'pageName' => wp_get_document_title(),
        'userStatus' => $user_status,
        'userRole' => $user_role,
        'language' => get_bloginfo('language'),
        'siteEnvironment' => defined('WP_ENVIRONMENT_TYPE') ? WP_ENVIRONMENT_TYPE : 'production'
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($data_layer); ?>);
    </script>
    <?php
}

Blog Post Data Layer

Enhanced data for blog posts and articles:

add_action('wp_head', 'blog_post_data_layer');
function blog_post_data_layer() {
    if (!is_single()) {
        return;
    }

    global $post;

    // Get post categories and tags
    $categories = wp_get_post_categories($post->ID, array('fields' => 'names'));
    $tags = wp_get_post_tags($post->ID, array('fields' => 'names'));

    // Calculate reading time
    $word_count = str_word_count(strip_tags($post->post_content));
    $reading_time = ceil($word_count / 200); // 200 words per minute

    // Get author info
    $author_id = $post->post_author;
    $author_name = get_the_author_meta('display_name', $author_id);

    // Get post age
    $publish_date = get_the_date('Y-m-d', $post);
    $days_since_publish = floor((time() - strtotime($post->post_date)) / (60 * 60 * 24));

    $post_data = array(
        'event' => 'blogPostView',
        'pageType' => 'blog-post',
        'postID' => $post->ID,
        'postTitle' => get_the_title($post),
        'postAuthor' => $author_name,
        'postAuthorID' => $author_id,
        'postCategories' => implode('|', $categories),
        'postTags' => implode('|', $tags),
        'publishDate' => $publish_date,
        'daysSincePublish' => $days_since_publish,
        'wordCount' => $word_count,
        'readingTimeMinutes' => $reading_time,
        'commentCount' => get_comments_number($post),
        'hasComments' => get_comments_number($post) > 0 ? 'yes' : 'no'
    );

    // Add custom fields if present
    $featured = get_post_meta($post->ID, '_featured_post', true);
    if ($featured) {
        $post_data['featuredPost'] = 'yes';
    }
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($post_data); ?>);
    </script>
    <?php
}

WooCommerce Data Layer

Product Page Data Layer

add_action('wp_footer', 'woocommerce_product_data_layer');
function woocommerce_product_data_layer() {
    if (!function_exists('is_product') || !is_product()) {
        return;
    }

    global $product;

    // Get product categories
    $categories = wp_get_post_terms($product->get_id(), 'product_cat', array('fields' => 'names'));

    // Get product attributes
    $attributes = array();
    foreach ($product->get_attributes() as $attr_name => $attr) {
        $attributes[] = wc_attribute_label($attr_name);
    }

    // Check stock status
    $stock_status = $product->is_in_stock() ? 'in-stock' : 'out-of-stock';
    $stock_quantity = $product->get_stock_quantity();

    // Get price information
    $regular_price = $product->get_regular_price();
    $sale_price = $product->get_sale_price();
    $on_sale = $product->is_on_sale();

    $product_data = array(
        'event' => 'productView',
        'ecommerce' => array(
            'detail' => array(
                'products' => array(
                    array(
                        'id' => $product->get_sku() ?: $product->get_id(),
                        'name' => $product->get_name(),
                        'price' => $product->get_price(),
                        'brand' => get_post_meta($product->get_id(), '_brand', true),
                        'category' => implode('/', $categories),
                        'variant' => $product->is_type('variable') ? 'variable' : 'simple',
                        'stockStatus' => $stock_status,
                        'stockQuantity' => $stock_quantity,
                        'onSale' => $on_sale ? 'yes' : 'no'
                    )
                )
            )
        ),
        'productID' => $product->get_id(),
        'productName' => $product->get_name(),
        'productType' => $product->get_type(),
        'productPrice' => $product->get_price(),
        'productSKU' => $product->get_sku(),
        'productCategories' => implode('|', $categories),
        'productAttributes' => implode('|', $attributes)
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($product_data); ?>);
    </script>
    <?php
}

Cart Data Layer

add_action('wp_footer', 'woocommerce_cart_data_layer');
function woocommerce_cart_data_layer() {
    if (!function_exists('is_cart') || !is_cart()) {
        return;
    }

    $cart = WC()->cart;
    $cart_items = array();

    foreach ($cart->get_cart() as $cart_item_key => $cart_item) {
        $product = $cart_item['data'];
        $cart_items[] = array(
            'id' => $product->get_sku() ?: $product->get_id(),
            'name' => $product->get_name(),
            'price' => $product->get_price(),
            'quantity' => $cart_item['quantity']
        );
    }

    $cart_data = array(
        'event' => 'cartView',
        'pageType' => 'cart',
        'cartValue' => floatval($cart->get_cart_contents_total()),
        'cartQuantity' => $cart->get_cart_contents_count(),
        'cartItemCount' => count($cart->get_cart()),
        'hasCoupon' => !empty($cart->get_applied_coupons()) ? 'yes' : 'no',
        'appliedCoupons' => implode('|', $cart->get_applied_coupons()),
        'ecommerce' => array(
            'currencyCode' => get_woocommerce_currency(),
            'cart' => array(
                'products' => $cart_items
            )
        )
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($cart_data); ?>);
    </script>
    <?php
}

Checkout Data Layer

add_action('woocommerce_before_checkout_form', 'woocommerce_checkout_data_layer');
function woocommerce_checkout_data_layer() {
    $cart = WC()->cart;
    $checkout_items = array();

    foreach ($cart->get_cart() as $cart_item_key => $cart_item) {
        $product = $cart_item['data'];
        $checkout_items[] = array(
            'id' => $product->get_sku() ?: $product->get_id(),
            'name' => $product->get_name(),
            'price' => $product->get_price(),
            'category' => wp_strip_all_tags(wc_get_product_category_list($product->get_id())),
            'quantity' => $cart_item['quantity']
        );
    }

    $checkout_data = array(
        'event' => 'checkoutView',
        'pageType' => 'checkout',
        'checkoutStep' => 1,
        'checkoutValue' => floatval($cart->get_cart_contents_total()),
        'checkoutTax' => floatval($cart->get_cart_contents_tax()),
        'checkoutShipping' => floatval($cart->get_shipping_total()),
        'checkoutTotal' => floatval($cart->get_total('')),
        'ecommerce' => array(
            'checkout' => array(
                'actionField' => array(
                    'step' => 1,
                    'option' => ''
                ),
                'products' => $checkout_items
            )
        )
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($checkout_data); ?>);
    </script>
    <?php
}

Purchase Confirmation Data Layer

add_action('woocommerce_thankyou', 'woocommerce_purchase_data_layer');
function woocommerce_purchase_data_layer($order_id) {
    if (!$order_id) {
        return;
    }

    // Prevent duplicate tracking
    $tracked = get_post_meta($order_id, '_gtm_datalayer_tracked', true);
    if ($tracked) {
        return;
    }

    $order = wc_get_order($order_id);
    $order_items = array();

    foreach ($order->get_items() as $item_id => $item) {
        $product = $item->get_product();
        $order_items[] = array(
            'id' => $product->get_sku() ?: $product->get_id(),
            'name' => $item->get_name(),
            'price' => $item->get_total() / $item->get_quantity(),
            'category' => wp_strip_all_tags(wc_get_product_category_list($product->get_id())),
            'quantity' => $item->get_quantity()
        );
    }

    $purchase_data = array(
        'event' => 'purchase',
        'pageType' => 'order-confirmation',
        'transactionId' => $order->get_order_number(),
        'transactionTotal' => floatval($order->get_total()),
        'transactionTax' => floatval($order->get_total_tax()),
        'transactionShipping' => floatval($order->get_shipping_total()),
        'transactionCurrency' => $order->get_currency(),
        'transactionPaymentMethod' => $order->get_payment_method_title(),
        'ecommerce' => array(
            'purchase' => array(
                'actionField' => array(
                    'id' => $order->get_order_number(),
                    'revenue' => floatval($order->get_total()),
                    'tax' => floatval($order->get_total_tax()),
                    'shipping' => floatval($order->get_shipping_total()),
                    'coupon' => implode('|', $order->get_coupon_codes())
                ),
                'products' => $order_items
            )
        )
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($purchase_data); ?>);
    </script>
    <?php

    // Mark as tracked
    update_post_meta($order_id, '_gtm_datalayer_tracked', 'yes');
}

Page Builder Data Layers

Elementor Data Layer

add_action('wp_footer', 'elementor_data_layer');
function elementor_data_layer() {
    if (!did_action('elementor/loaded')) {
        return;
    }

    global $post;

    // Check if page is built with Elementor
    $is_elementor = get_post_meta($post->ID, '_elementor_edit_mode', true);

    if ($is_elementor === 'builder') {
        ?>
        <script>
            dataLayer.push({
                'pageBuilder': 'elementor',
                'elementorVersion': '<?php echo ELEMENTOR_VERSION; ?>',
                'isElementorPage': 'yes'
            });
        </script>
        <?php
    }
}

Divi Data Layer

add_action('wp_footer', 'divi_data_layer');
function divi_data_layer() {
    if (!function_exists('et_divi_builder_init_plugin')) {
        return;
    }

    global $post;

    // Check if Divi Builder is enabled
    $divi_enabled = get_post_meta($post->ID, '_et_pb_use_builder', true);

    if ($divi_enabled === 'on') {
        ?>
        <script>
            dataLayer.push({
                'pageBuilder': 'divi',
                'isDiviPage': 'yes'
            });
        </script>
        <?php
    }
}

User-Based Data Layer

Membership and Roles

add_action('wp_head', 'user_membership_data_layer');
function user_membership_data_layer() {
    if (!is_user_logged_in()) {
        return;
    }

    $user = wp_get_current_user();
    $user_role = !empty($user->roles) ? $user->roles[0] : 'subscriber';

    // Calculate user account age
    $registration_date = get_userdata($user->ID)->user_registered;
    $account_age_days = floor((time() - strtotime($registration_date)) / (60 * 60 * 24));

    // Check for WooCommerce customer data
    $total_orders = 0;
    $lifetime_value = 0;
    if (function_exists('wc_get_customer_order_count')) {
        $total_orders = wc_get_customer_order_count($user->ID);
        $lifetime_value = wc_get_customer_total_spent($user->ID);
    }

    // Customer segment
    $customer_segment = 'new';
    if ($total_orders > 0) {
        $customer_segment = 'returning';
    }
    if ($total_orders > 5) {
        $customer_segment = 'loyal';
    }
    if ($lifetime_value > 1000) {
        $customer_segment = 'vip';
    }

    $user_data = array(
        'userID' => $user->ID,
        'userEmail' => hash('sha256', $user->user_email), // Hashed for privacy
        'userRole' => $user_role,
        'accountAgeDays' => $account_age_days,
        'totalOrders' => $total_orders,
        'lifetimeValue' => $lifetime_value,
        'customerSegment' => $customer_segment
    );
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($user_data); ?>);
    </script>
    <?php
}

Event-Based Data Layer Pushes

Form Submission Events

add_action('wp_footer', 'form_submission_data_layer');
function form_submission_data_layer() {
    ?>
    <script>
        // Contact Form 7
        document.addEventListener('wpcf7mailsent', function(event) {
            dataLayer.push({
                'event': 'formSubmission',
                'formType': 'contact-form-7',
                'formID': event.detail.contactFormId,
                'formName': event.detail.unitTag
            });
        });

        // Gravity Forms
        jQuery(document).on('gform_confirmation_loaded', function(event, formId) {
            dataLayer.push({
                'event': 'formSubmission',
                'formType': 'gravity-forms',
                'formID': formId
            });
        });

        // WPForms
        jQuery(document).on('wpformsAjaxSubmitSuccess', function(event, data) {
            dataLayer.push({
                'event': 'formSubmission',
                'formType': 'wpforms',
                'formID': data.form_id
            });
        });
    </script>
    <?php
}

WooCommerce Add-to-Cart Events

add_action('wp_footer', 'add_to_cart_data_layer_event');
function add_to_cart_data_layer_event() {
    if (!is_product()) {
        return;
    }

    global $product;
    ?>
    <script>
        jQuery(document).ready(function($) {
            $('.single_add_to_cart_button').on('click', function() {
                const quantity = parseInt($('.qty').val() || 1);
                const price = parseFloat('<?php echo $product->get_price(); ?>');

                dataLayer.push({
                    'event': 'addToCart',
                    'ecommerce': {
                        'add': {
                            'products': [{
                                'id': '<?php echo esc_js($product->get_sku() ?: $product->get_id()); ?>',
                                'name': '<?php echo esc_js($product->get_name()); ?>',
                                'price': price,
                                'quantity': quantity
                            }]
                        }
                    }
                });
            });
        });
    </script>
    <?php
}

Custom Dimensions and Metrics

WordPress-Specific Custom Dimensions

add_action('wp_head', 'custom_dimensions_data_layer');
function custom_dimensions_data_layer() {
    global $post;

    $custom_data = array();

    // Site-specific data
    $custom_data['siteID'] = get_current_blog_id(); // For multisite
    $custom_data['themeVersion'] = wp_get_theme()->get('Version');
    $custom_data['wpVersion'] = get_bloginfo('version');

    // Content age segmentation
    if (isset($post->post_date)) {
        $content_age_days = floor((time() - strtotime($post->post_date)) / (60 * 60 * 24));
        if ($content_age_days <= 7) {
            $custom_data['contentAge'] = 'new';
        } elseif ($content_age_days <= 30) {
            $custom_data['contentAge'] = 'recent';
        } elseif ($content_age_days <= 180) {
            $custom_data['contentAge'] = 'medium';
        } else {
            $custom_data['contentAge'] = 'old';
        }
    }

    // Traffic source context
    if (isset($_SERVER['HTTP_REFERER'])) {
        $referrer = $_SERVER['HTTP_REFERER'];
        if (strpos($referrer, 'google.com') !== false) {
            $custom_data['trafficSource'] = 'google';
        } elseif (strpos($referrer, 'facebook.com') !== false) {
            $custom_data['trafficSource'] = 'facebook';
        }
    }
    ?>
    <script>
        dataLayer.push(<?php echo json_encode($custom_data); ?>);
    </script>
    <?php
}

Accessing Data Layer in GTM

Create Data Layer Variables

In GTM:

Variables → New → Data Layer Variable
Name: Page Type
Data Layer Variable Name: pageType
Save

Repeat for all data layer keys (postID, productName, userRole, etc.)

Use in Tags

Example GA4 Event Tag:

Event Name: blog_post_view
Event Parameters:
- post_id: \{\{DLV - postID\}\}
- post_author: \{\{DLV - postAuthor\}\}
- post_category: \{\{DLV - postCategories\}\}

Use in Triggers

Example trigger for logged-in users:

Trigger Type: Page View - DOM Ready
Condition: \{\{DLV - userStatus\}\} equals logged-in

Debugging the Data Layer

Console Inspection

// View entire dataLayer
console.table(dataLayer);

// Watch for new pushes
const originalPush = dataLayer.push;
dataLayer.push = function() {
    console.log('dataLayer.push:', arguments[0]);
    return originalPush.apply(this, arguments);
};

GTM Preview Mode

Open GTM → Preview
Enter WordPress site URL
Click Variables tab
Verify all Data Layer Variables populate correctly

DataLayer Checker Chrome Extension

Install dataslayer to visualize data layer in real-time.

Performance Considerations

Lazy Load Data Layer for Non-Critical Pages

// Only build complex data layer on pages that need it
add_action('wp_head', 'conditional_data_layer');
function conditional_data_layer() {
    // Full data layer for product/checkout pages
    if (is_product() || is_checkout() || is_cart()) {
        woocommerce_full_data_layer();
    } else {
        // Minimal data layer for blog posts
        basic_wordpress_data_layer();
    }
}

Next Steps

GTM Data Layer Fundamentals - Universal concepts
GTM Setup Guide - Install GTM on WordPress
WordPress Integrations - Overview of all tracking options

WordPress Data Layer for GTM

WordPress Data Layer for GTM

Understanding the Data Layer

Benefits of a Proper Data Layer

Data Layer Structure

Basic WordPress Data Layer

Initialize Data Layer Before GTM

Blog Post Data Layer

WooCommerce Data Layer

Product Page Data Layer

Cart Data Layer

Checkout Data Layer

Purchase Confirmation Data Layer

Page Builder Data Layers

Elementor Data Layer

Divi Data Layer

User-Based Data Layer

Membership and Roles

Event-Based Data Layer Pushes

Form Submission Events

WooCommerce Add-to-Cart Events

Custom Dimensions and Metrics

WordPress-Specific Custom Dimensions

Accessing Data Layer in GTM

Create Data Layer Variables

Use in Tags

Use in Triggers

Debugging the Data Layer

Console Inspection

GTM Preview Mode

DataLayer Checker Chrome Extension

Performance Considerations

Lazy Load Data Layer for Non-Critical Pages

Next Steps

Related Resources