How to send data from a GTM Server-Side container to Batch?

Here is how to send events from a GTM Server-Side container to Batch using a custom HTTP Request tag.

Google Tag Manager Server-Side (sGTM) lets you collect events on your website via a lightweight client-side snippet and forward them to your own server container before redistributing them to downstream tools. This guide explains how to route those events to Batch using the Profile API.

The connection between your sGTM container and Batch must be implemented by your technical team using a custom HTTP Request tag.

Prerequisites

Before you start, make sure you have:

• A Google Tag Manager Server-Side container deployed on a first-party subdomain (e.g. collect.yourdomain.com).
• The Batch REST API Key and Project Key for your project (available in your Batch dashboard).
• The Batch installation_id and/or custom_id exposed in your dataLayer at the time events are triggered.

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Step 1: Expose the Batch identifier in the dataLayer

The Profile API requires an identifier to target the correct Batch profile. Both options below run client-side, in the page — not inside the sGTM container. The sGTM container reads these values from the dataLayer via Data Layer Variables (see Step 2).

Option A — Custom User ID (authenticated users)

The custom_id comes from your own authentication system. Push it to the dataLayer when the user logs in or when the page loads for an authenticated session.

The value must be the same stable identifier you use to identify users in your systems (login ID, hashed email, etc.).

Option B — Installation ID (anonymous users)

The Batch Web SDK generates an installation_id automatically. Retrieve it client-side using the SDK and push it to the dataLayer:

// Run client-side, after the Batch SDK has initialized
batchSDK(function(api) {
  api.getInstallationID().then(function(installationId) {
    window.dataLayer = window.dataLayer || [];
    window.dataLayer.push({ batch_installation_id: installationId });
  });
});

Both snippets must execute client-side, in the browser, before any sGTM event fires. Push the identifier as early as possible in the page lifecycle to ensure it is available for all subsequent events captured by the sGTM container.

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Step 2: Create the dataLayer variables in your sGTM container

In your sGTM container, create Data Layer Variable variables to read the identifiers you pushed in Step 1.

1. Go to Variables > New.
2. Select Data Layer Variable as the variable type.
3. Set the Data Layer Variable Name to custom_id (repeat for installation_id if needed).
4. Save the variable.

Repeat this step for any event attributes you want to forward to Batch (e.g. ecommerce.value, event, etc.).

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Step 3: Create the custom HTTP Request tag

1. In your sGTM container, go to Tags > New.
2. Select HTTP Request as the tag type.
3. Configure the tag as follows:

Request URL

https://api.batch.com/2.11/profiles/update

Method: POST

Headers

Key	Value
Content-Type	application/json
Authorization	Bearer {{Batch REST API Key}}
X-Batch-Project	{{Batch Project Key}}

Store your REST API Key as a Constant variable with type: Secret in your sGTM container. Never expose it in client-side code.

Request Body

Build the JSON body dynamically using your sGTM variables. The structure depends on whether you identify users by custom_id or installation_id.

With a Custom User ID:

[
  {
    "identifiers": {
      "custom_id": "{{batch_custom_id}}"
    },
    "attributes": {
      "your_attribute": "{{your_variable}}"
    },
    "events": [
      {
        "name": "{{event_name}}",
        "attributes": {
          "$label": "{{event_label}}"
        }
      }
    ]
  }
]

With an Installation ID:

[
  {
    "identifiers": {
      "installation": {
        "apikey": "{{Batch API Key}}",
        "installation_id": "{{batch_installation_id}}"
      }
    },
    "events": [
      {
        "name": "{{event_name}}"
      }
    ]
  }
]

1. Save the tag.

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Step 4: Set the trigger

Configure the tag to fire on the events you want to forward to Batch (e.g. purchase, add_to_cart, page_view).

1. In the tag settings, click Triggering.
2. Select an existing trigger or create a new one based on the event name.
3. Save.

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Step 5: Test and publish

1. Use the Preview mode in GTM to verify the tag fires correctly on the expected events.
2. Check that the HTTP request reaches the Batch API and returns a 202 response.
3. Verify that the profile is updated in the Batch dashboard.
4. Once validated, publish your sGTM container.

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Notes

• If both custom_id and installation_id are available, prefer custom_id to ensure correct profile stitching across channels.
• For more details on the available fields, constraints and rate limits, see the Profile API reference documentation.