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Customer.io

Send site events and visitor identity to Customer.io only after visitors allow marketing. On withdrawal, c15t clears the identity and reloads.

Inth keeps the consent record of each choice, with the visitor’s country and the policy that applied.

Start for free
pnpm add @c15t/integrations
Customer.ioWaiting for consent
Before a choice

Allow only another category. No snippet request, cioanalytics global, cookie or storage appears.

Turn the switch on, then off, to see what loads.

Before you start

You need an Inth project that connects to your app and c15t in that app. You also need the write key of a JavaScript source in Customer.io Data Pipelines.

Note the region of your workspace. A proxy must pass requests to the regional host of the source.

Open the quickstart for your framework

How consent works with Customer.io

Before marketing has permission, the c15t customerIo helper creates no cioanalytics global and downloads no SDK.

After permission, the helper sets up the queue and loads the SDK. It sends the first page() call itself, so it sets initialPageview to false.

While the SDK downloads, calls such as cioanalytics.identify('customer-123').track('Signed up') queue in order.

On withdrawal, the helper calls reset() to clear the stored identity. reset() is not an opt out. So keep reloadOnConsentRevoked on to stop the SDK.

Installation

Customer.io has one load mode in c15t. The helper waits for marketing permission.

Wait for permission. No request goes to Customer.io until the visitor accepts marketing. On withdrawal, c15t clears the identity and reloads.

customerIo({ writeKey })

An opt-out policy or no policy gives optional categories permission before a choice. Then Customer.io loads on the first page. This guide uses an opt-in policy.

Setup steps

  1. Install the integration package

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

    pnpm add @c15t/integrations
  2. Add your write key

    The helper copies loadOptions, so your object stays the same. The SDK loads once per page.

    src/consent-scripts.ts
    import { customerIo } from '@c15t/integrations/customer-io';
    
    export const scripts = [customerIo({ writeKey: 'YOUR_WRITE_KEY' })];

    cioanalytics does not exist before consent. Check marketing permission before your own code calls it.

  3. Use a proxy (optional)

    Set cdnUrl to the origin of your proxy for the SDK and settings. To move event collection too, set apiHost and protocol in loadOptions. Replace both example domains with your own.

    src/customer-io-proxy.ts
    import { customerIo } from '@c15t/integrations/customer-io';
    
    export const proxiedScripts = [
      customerIo({
        cdnUrl: 'https://analytics.example.com',
        loadOptions: {
          integrations: {
            'Customer.io Data Pipelines': {
              apiHost: 'collect.example.com/v1',
              protocol: 'https',
            },
          },
        },
        writeKey: 'YOUR_WRITE_KEY',
      }),
    ];
  4. Register 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.

    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.

    c15t.config.ts
    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.

    src/routes/__root.tsx
    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.

    src/consent.tsx
    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.

    app/app.config.ts
    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.

    src/main.ts
    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.

    src/c15t.client.ts
    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.

    src/App.svelte
    <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.

    src/routes/+layout.svelte
    <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.

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

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

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

Remove the original Customer.io snippet, so c15t controls when it loads.

Verify your setup

Use a private window with an opt-in policy. Open DevTools Network and filter by customer.io or your proxy domain.

  • Before a choice

    Allow only another category. No snippet request, cioanalytics global, cookie or storage appears.

  • After you allow marketing

    The SDK starts. A 200 response for a wrong write key does not prove this, so check with your real key.

  • After you withdraw marketing

    c15t reloads the page, and the next page stays quiet.

With a proxy, check that the settings and SDK files come from your CDN proxy. Check event collection on the apiHost that you set.

Open the full Customer.io guide