Google Tag Manager

Installation

The helper has two modes for when gtm.js loads. Pick the mode that your policy needs.

With after-consent, an opt-out policy or no policy gives optional categories permission before a choice. Then gtm.js loads on the first page. If the container holds only Analytics tags, pass category: 'measurement'.

Setup steps

1. 1Install the integration package

   Add the helpers next to c15t. An import alone does not start the container.

   npmpnpmyarnbun

   npm install @c15t/integrations

   pnpm add @c15t/integrations

   yarn add @c15t/integrations

   bun add @c15t/integrations

2. 2Add your container ID

   The helper trims the ID. An empty ID logs an error, and the container does not load.

   import { googleTagManager } from '@c15t/integrations/google-tag-manager';
   
   export const scripts = [googleTagManager({ id: 'GTM-XXXXXXX' })];

   To hold the container until consent, add loadMode: 'after-consent' to the same call.

3. 3Register it with your existing setup

   Add scripts to the c15t configuration that you have now. Keep your Inth endpoint, mode, policy, styles and consent UI.

   Next.jsTanStack StartReactNuxtVueAstroSvelteSvelteKitHTMLJavaScript

   Add scripts to c15t.config.ts, next to next.config.ts. Keep the rest of your config, such as mode, in the same call. App Router, Pages Router and static export read the same file.

   import { defineConsentConfig } from 'c15t/next';
   import { scripts } from './src/consent-scripts';
   
   export default defineConsentConfig({ scripts });

   Pass scripts to the ConsentRoot in your root route. Import helpers in the route module, not in a server function: script configurations carry callbacks.

   import { scripts } from '../consent-scripts';
   
   <ConsentRoot state={consent} scripts={scripts}>

   Add scripts to the options of your ConsentProvider, next to mode. Keep the banner, dialog and preferences link inside the provider.

   import { scripts } from './consent-scripts';
   
   <ConsentProvider options={{ mode, scripts }}>

   Register scripts under the c15t key in app.config.ts. Keep them out of nuxt.config.ts, which reaches the browser as JSON and drops the helper callbacks.

   import { scripts } from '../src/consent-scripts';
   
   export default defineAppConfig({
     c15t: { scripts },
   });

   Pass scripts to the c15tVue plugin call you have now. The plugin starts one script loader when the app mounts.

   import { c15tVue, manifest } from 'c15t/vue/vue-plugin';
   import { scripts } from './consent-scripts';
   
   app.use(c15tVue, {
     mode: manifest(),
     scripts,
   });

   Add scripts to the client entrypoint, which the integration finds on its own. Keep helpers out of astro.config.mjs: its options are serialized into the page.

   import type { C15tClientOptionsExtension } from 'c15t/astro';
   import { scripts } from './consent-scripts';
   
   export default { scripts } satisfies C15tClientOptionsExtension;

   Pass scripts as a prop to the ConsentProvider you have now. The provider owns the loader and disposes it on unmount.

   <script lang="ts">
     import { ConsentProvider, manifest } from 'c15t/svelte';
     import { scripts } from './consent-scripts';
   </script>
   
   <ConsentProvider mode={manifest()} {scripts}>
     <!-- Your app and consent UI -->
   </ConsentProvider>

   Add scripts to the ConsentRoot in the root layout. Import helpers in the layout component, not in +layout.server.ts: a server load cannot send functions to the browser.

   <script lang="ts">
     import { ConsentRoot } from 'c15t/svelte';
     import { scripts } from '../consent-scripts';
   
     let { children, data } = $props();
   </script>
   
   <ConsentRoot state={data.consent} {scripts}>
     {@render children()}
   </ConsentRoot>

   Paste the vendor’s snippet behind consent

   The helpers need a bundler. On a page with the c15t script tag, paste the vendor’s own snippet instead and keep it inert until visitors allow its category. Helper options, such as loadMode, do not apply.

   <script type="text/plain" data-c15t-category="measurement">
     // The vendor's snippet, unchanged
   </script>

   Pass scripts to init() from @c15t/browser, next to your mode. With createConsentRuntime, pass scripts to it instead.

   import { init, manifest } from '@c15t/browser';
   import { scripts } from './consent-scripts';
   
   const consent = init({
     mode: manifest(),
     scripts,
   });

Use the helper or the c15t Consent Management template from the GTM Community Template Gallery on a page, never both. Otherwise Google receives two sets of consent commands.