# Amplitude

The c15t amplitude helper loads the Amplitude Browser SDK only after visitors allow measurement in Inth. On withdrawal, it opts the SDK out, and a later grant opts it back in.

## Key facts

- **Tool:** Amplitude
- **Category:** Analytics
- **Consent categories:** Measurement
- **Setup method:** c15t package
- **Package:** @c15t/integrations

## Links

- [Documentation](https://c15t.com/docs/integrations/amplitude)
- [Amplitude](https://amplitude.com/)

Keep the Amplitude Browser SDK off the page until visitors allow measurement. A withdrawal opts the SDK out, and a later grant clears that opt-out.

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, c15t in that app and the project API key from Amplitude.

New to c15t? Complete the quickstart for your framework first. Keep its Inth endpoint, policy, styles and consent UI.

[Open the quickstart for your framework](https://c15t.com/docs/frameworks)

## How consent gets to Amplitude

Before measurement has permission, c15t defines no window.amplitude and loads nothing from Amplitude.

After permission, the c15t amplitude helper creates the Browser SDK 2 queue. It queues init and setOptOut(false), then loads the SDK. The SDK replays the queue.

Amplitude keeps an opt-out in its cookie. The queued setOptOut(false) clears an opt-out from an earlier withdrawal.

On withdrawal, the helper calls amplitude.setOptOut(true). The SDK stays on the page, and c15t reloads the page by default.

## Installation

Amplitude has one load mode in c15t. The helper waits for measurement permission.

### Wait for permission

No request goes to Amplitude until the visitor accepts measurement. On withdrawal, the helper opts the SDK out.

```ts
amplitude({ apiKey })
```

An opt-out policy or no policy gives optional categories permission before a choice. Then Amplitude 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 the Amplitude SDK.

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

#### Add your project API key

The helper sends the key to amplitude.init. Pass Browser SDK 2 options in initOptions, with JSON values only.

```
import { amplitude } from '@c15t/integrations/amplitude';

export const scripts = [amplitude({ apiKey: 'YOUR_PROJECT_API_KEY' })];
```

An empty API key logs an error, and the script does not load. The default script URL pins Browser SDK 2 version 2.44.4.

### 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="measurement">
  // 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,
});
```

The helper calls init for you. Remove the old Amplitude snippet and each init call. If you already have a scripts array, add the helper to it.

## Verify your setup

Use a private window with an opt-in policy. Open DevTools Network and filter by amplitude. Then test the three states.

- **Before a choice**: No request goes to cdn.amplitude.com. In the Console, window.amplitude returns undefined.

- **After you allow measurement**: analytics-browser-2.44.4-min.js.gz loads without a page reload. A test event gets to your Amplitude project.

- **After you withdraw measurement**: Save your choice. c15t reloads the page. Allow measurement again on a later page and make sure that events get to Amplitude again.

If your code calls window.amplitude.track directly, check measurement permission before each call.

[Open the full Amplitude guide](https://c15t.com/docs/integrations/amplitude)

## Related guides

- [Gainsight PX](/integrations/gainsight-px)

- [Heap](/integrations/heap)

- [Mixpanel](/integrations/mixpanel-analytics)