Google Tag Manager on Bolt CMS | OpsBlu Docs

Google Tag Manager on Bolt CMS

How to install and configure Google Tag Manager on Bolt CMS. Covers installation method, container setup, verification, and Bolt CMS-specific...

For general GTM concepts, see Google Tag Manager Overview

Overview

Bolt CMS uses Twig templates (built on Symfony). Add GTM by editing your theme's base template.

Prerequisites

Installation

Where to Add GTM Code

Edit templates/base.html.twig (or _base.html.twig depending on theme) — add head snippet in {% block head %} and body snippet after <body> tag

GTM Head Snippet

Add this in the <head> section:

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->

GTM Body Snippet

Add this immediately after the opening <body> tag:

<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->

Replace GTM-XXXXXXX with your actual Container ID in both snippets.

Bolt CMS-Specific Considerations

Bolt CMS v5+ uses Symfony's Twig templating. The base template location varies by theme. Check theme.yaml for the layout file path. Use {{ block('head') }} to extend rather than replace.

Template System

Bolt CMS uses Twig templates in public/theme/your-theme/. When editing templates directly, note that the GTM JavaScript snippet (inside <script> tags) will not conflict with the template engine's syntax.

Verification

After installation, verify GTM is working:

  1. GTM Preview Mode — In GTM, click Preview, enter your site URL, and verify the container loads.
  2. Browser Console — Open DevTools (F12) and run console.log(window.google_tag_manager). You should see an object (not undefined).
  3. Network Tab — Filter for googletagmanager.com and verify gtm.js loads with a 200 response.
  4. Data Layer Check — Run console.log(window.dataLayer) to verify the data layer array exists.

Next Steps

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