> For the complete documentation index, see [llms.txt](https://developer.paddle.com/llms.txt).

# Authenticate using client-side tokens

Pass a client-side token when initializing to authenticate with Paddle.js. There's no need to pass your seller ID anymore.

---

## What's new?

We added [client-side tokens](https://developer.paddle.com/paddlejs/client-side-tokens.md) to the Paddle platform. As part of this update, you can pass a client-side token to the [`Paddle.Initialize()`](https://developer.paddle.com/paddlejs/methods/paddle-initialize.md) method to authenticate.

- **token** (string): Client-side token for authentication. You can create and manage client-side tokens in Paddle > Developer tools > Authentication. Required

This supersedes the `seller` parameter that was used previously.

## How it works

Client-side tokens let you authenticate with the Paddle platform in your frontend. They work with Paddle.js to handle working with pricing information and securely capturing payment details.

You can create and manage client-side tokens in **Paddle > Developer tools > Authentication**. This page has been redesigned to make it easier to work with API keys and client-side tokens.

### Client-side tokens vs API keys

[API keys](https://developer.paddle.com/api-reference/about/api-keys.md) are designed for working with the Paddle API in your backend. They have full access to the data in your system. You must store them securely and keep them secret.

Unlike API keys, client-side tokens may be published in your app code. They're designed for working with the Paddle platform in your frontend. They have limited access to the data in your system.

### Paddle.Initialize() changes

Previously, we recommended passing the `seller` parameter with your seller ID to the [`Paddle.Initialize()`](https://developer.paddle.com/paddlejs/methods/paddle-initialize.md) method. Now, you can use the `token` parameter with a client-side token instead. We've updated our docs to reflect this new way of working.

Existing methods that use `seller` will continue to work, but future methods may require client-side tokens. We recommend that you replace the `seller` parameter with `token` and a client-side token when you're next reviewing your code.

## Examples

This example shows how you [include and initialize Paddle.js with Retain](https://developer.paddle.com/paddlejs/include-paddlejs.md).

### Before

```html {% title="Using seller ID" highlightLines="4" %}
<script src="https://cdn.paddle.com/paddle/v2/paddle.js"></script>
<script type="text/javascript">
  Paddle.Initialize({
    seller: 99999,
    pwCustomer: { }
  });
</script>
```

### After

```html {% title="Using a client-side token" highlightLines="4" %}
<script src="https://cdn.paddle.com/paddle/v2/paddle.js"></script>
<script type="text/javascript">
  Paddle.Initialize({
    token: 'live_7d279f61a3499fed520f7cd8c08',
    pwCustomer: { }
  });
</script>
```

## Next steps

This change is live now, so you can start using a client-side token to authenticate when using Paddle.js.

You don't need to do anything to get the latest version of Paddle.js — we serve the latest version automatically.
## Summary of changes

| Name | Type | Change | Entity | Description |
| --- | --- | --- | --- | --- |
| `token` | Paddle.js param | added | Paddle.Initialize() | Client-side token for authentication; replaces seller ID. |