Datalayer requirements for ProfitMetrics client-side Google Tag Manager integration

DataLayer Requirements for Client-Side GTM Integration

Supported DataLayer Formats

The tag auto-detects your dataLayer format by checking for these structures in order:

1. GA Enhanced Ecommerce (UA) — ecommerce.purchase.actionField
2. GA4 Ecommerce — ecommerce.transaction_id
3. GA4 via eventModel — eventModel.transaction_id
4. Legacy — transactionId
5. Custom — Fields mapped manually in the GTM tag configuration

You can also force a specific format using the "Select dataLayer type for quick set up" dropdown, or choose Custom to map each field individually using GTM variables.

Required Fields

These fields must be present in your dataLayer for the tag to function correctly. The exact field paths depend on your dataLayer format.

GA4 Ecommerce (ecommerce.transaction_id)

UA Enhanced Ecommerce (ecommerce.purchase.actionField)

GA4 via eventModel (eventModel.transaction_id)

Legacy (transactionId)

Note: Currency and Coupon Code are not supported in the Legacy format.

Product Array

Each item in the products array must include:

Note on price: If your product prices include tax, enable the "Products include tax" setting in the GTM tag. The tag will automatically calculate the ex-VAT price using the derived tax rate.

Example (GA4 format)

{
  "event": "purchase",
  "ecommerce": {
    "transaction_id": "ORD-12345",
    "value": 150.00,
    "tax": 30.00,
    "shipping": 10.00,
    "currency": "EUR",
    "coupon": "SUMMER20",
    "items": [
      {
        "item_id": "SKU-001",
        "quantity": 2,
        "price": 50.00
      },
      {
        "item_id": "SKU-002",
        "quantity": 1,
        "price": 20.00
      }
    ]
  }
}

Optional Fields

These fields improve attribution accuracy and enable additional ProfitMetrics features. They are configured directly in the GTM tag settings (not read from the dataLayer automatically).

Tax & Revenue Settings

The tag needs to understand how your platform reports tax, revenue, and shipping in order to calculate accurate ex-VAT and incl-VAT totals. Configure these in the Tax settings section:

If these settings are incorrect, ProfitMetrics will calculate incorrect profit margins. If you are unsure, check a sample order against your platform admin to verify.

Custom Field Overrides

The Custom fields (Override) section in the tag lets you override any of the core order fields. This is useful when your dataLayer doesn't match any of the standard formats, or when you need to pull a value from a GTM variable.

Override fields available: Transaction id, Revenue, Tax, Shipping, Currency, Coupon Code, Products (Array).

When a custom field is populated, it takes priority over the auto-detected dataLayer value.

Consent Handling

The tag reads consent state from the window.profitMetrics object, which is set by the ProfitMetrics 'All pages' GTM tag template:

• profitMetrics.cookieStatisticsConsent — Controls whether GA cookies (_ga, _ga_*, pmGacid, pmVisitSource) are read
• profitMetrics.cookieMarketingConsent — Controls whether marketing cookies (pmGclid, pmGbraid, pmWbraid, _fbp, _fbc) are read

If consent is not granted, the tag still sends the order data but without cookie-based attribution parameters. No cookies are read without the corresponding consent.

Troubleshooting

Enable Debug Mode in the tag settings to log detailed output to the browser console. This will show you exactly which dataLayer format was detected, what values were read, and the full URL being sent to ProfitMetrics.