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

# Multi-Instance Support

> Managing multiple WhatsApp numbers with a single API key

Organizations with multiple WhatsApp numbers can control which instance sends each message using the `from` parameter.

## How It Works

When your organization has multiple connected WhatsApp instances:

1. **Without `from`**: API selects the most recently connected instance
2. **With `from`**: API uses the specified instance

## Specifying the Sender

The `from` parameter accepts two formats:

| Format       | Example         | Description                        |
| ------------ | --------------- | ---------------------------------- |
| Phone number | `5585912345678` | WhatsApp number without `+` or `@` |
| Instance ID  | `uuid-xxx-xxx`  | Internal instance identifier       |

<Tip>Phone numbers are the recommended format as they're easier to remember and manage.</Tip>

## Example Usage

### Send from a specific number

```bash theme={null}
curl -X POST https://api.livchat.ai/v1/messages/send \
  -H "Authorization: Bearer lc_live_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "phone": "5511999999999",
    "body": "Message from Sales department",
    "from": "5585912345678"
  }'
```

### Use different numbers for different purposes

```javascript theme={null}
// Sales messages from sales number
await api.send({
  phone: customerPhone,
  body: "Your order has been confirmed!",
  from: SALES_WHATSAPP_NUMBER,
});

// Support messages from support number
await api.send({
  phone: customerPhone,
  body: "Your ticket #123 has been resolved",
  from: SUPPORT_WHATSAPP_NUMBER,
});
```

## Default Behavior

If you don't specify `from`:

* **Single instance**: The only available instance is used
* **Multiple instances**: The most recently connected instance is automatically selected

<Warning>
  For organizations with multiple numbers, we recommend always specifying `from` to ensure predictable behavior.
</Warning>

## Error Handling

If you specify an invalid `from` value:

```json theme={null}
{
  "error": {
    "code": 403,
    "message": "Instance not found or not authorized: 5500000000000",
    "hint": "Use a valid phone number or instance ID from your organization"
  }
}
```

## Best Practices

<CardGroup cols={2}>
  <Card title="Use environment variables" icon="gear">
    Store your WhatsApp numbers in environment variables for easy management across environments.
  </Card>

  <Card title="Map numbers to departments" icon="building">
    Create a mapping of department names to phone numbers for cleaner code.
  </Card>

  <Card title="Always specify from" icon="check">
    For multi-instance orgs, always specify `from` to avoid unexpected behavior.
  </Card>

  <Card title="Monitor instance status" icon="chart-line">
    Ensure your instances are connected before sending messages.
  </Card>
</CardGroup>