> ## Documentation Index
> Fetch the complete documentation index at: https://betterdatainc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> Secure your gateway and manage access

The LLM Gateway provides several layers of authentication to ensure that only authorized users and AI agents can access your commerce capabilities.

## Gateway Authentication

This controls who can call the gateway's tools. It is primarily used when you are hosting your own gateway instance.

### API Keys

You can configure a list of valid API keys. The gateway will look for these in the `Authorization` header.

```typescript theme={null}
const gateway = new LLMGateway({
  auth: {
    apiKeys: [process.env.INTERNAL_API_KEY]
  }
});
```

### JWT (JSON Web Tokens)

For web-based integrations, you can use JWTs to authenticate users who are already logged into your storefront.

## User Authentication

When an LLM calls a tool like `create_order`, you often need to know the identity of the end-user.

1. **Anonymous**: Most shopping starts anonymously with just a `sessionId`.
2. **Linked**: You can link a `sessionId` to a specific `userId` in your system after the user logs in via a secure link.

## Merchant Authentication (Multi-vendor)

In a marketplace or hub environment, each merchant might have their own credentials. The gateway handles this via "Backend Credentials" stored securely in your database or managed by the [Better Data Cloud](/hosted/overview).

## Signal Tags

For the highest level of security in conversational commerce, the Better Data platform supports **Signal Tags**. These are authenticated physical or digital tags that provide a "hardware-backed" proof of proximity or ownership, often used for reordering or premium support.

## Security Best Practices

* **Rotate Keys**: Regularly rotate your gateway API keys.
* **HTTPS Only**: Never run the gateway over unencrypted HTTP.
* **Limit Scopes**: Only give your AI agents access to the tools they absolutely need. e.g., an "Information Agent" likely doesn't need the `delete_order` capability.