# Customer.io

The c15t customerIo helper loads the Customer.io Data Pipelines SDK only after visitors allow marketing in Inth. On withdrawal, it calls reset and c15t reloads.

## Key facts

- **Tool:** Customer.io
- **Category:** Other
- **Consent categories:** Marketing
- **Setup method:** c15t package
- **Package:** @c15t/integrations

## Links

- [Documentation](https://c15t.com/docs/integrations/customer-io)
- [Customer.io](https://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](/dashboard/sign-up)

## 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](https://c15t.com/docs/frameworks)

## 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.

```ts
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

#### Install the integration package

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

```
pnpm add @c15t/integrations
```

#### Add your write key

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

```
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.

#### 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.

```
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',
  }),
];
```

### Register it with your existing setup

#### Next.js

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 });
```

#### TanStack Start

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}>
```

#### React

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 }}>
```

#### Nuxt

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 },
});
```

#### Vue

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,
});
```

#### Astro

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;
```

#### Svelte

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>
```

#### SvelteKit

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>
```

#### HTML: 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="marketing">
  // The vendor's snippet, unchanged
</script>
```

#### JavaScript

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,
});
```

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](https://c15t.com/docs/integrations/customer-io)

## Related guides

- [HubSpot](/integrations/hubspot)

- [Insider](/integrations/insider)

- [Klaviyo](/integrations/klaviyo)