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

# email

> Customer's email address. Primary identifier for cross-device tracking.

Customer's email address. Primary identifier for cross-device tracking and destination matching.

```javascript theme={null}
// With a lead form submission
window._upstack('track', 'lead', {
  email: 'customer@example.com',
  value: 0,
  currency: 'USD'
});

// With a purchase
window._upstack('track', 'purchase', {
  email: 'customer@example.com',
  transactionId: 'ORD-123',
  value: 99.99,
  currency: 'USD'
});
```

| Type   | Required    | Events                              |
| ------ | ----------- | ----------------------------------- |
| string | Recommended | All events (improves match quality) |

## Privacy

Email addresses are normalized (lowercase, trimmed) and SHA-256 hashed before being sent to advertising destinations. Raw emails are never stored in destination platforms.

<Tip>
  Events with email typically score EMQ 8-9 on Meta. Events with only IP address score 2-3.
</Tip>

## Related Properties

<CardGroup cols={2}>
  <Card title="phone" icon="phone" href="/pixel/events/properties/phone">
    Customer phone number for improved matching.
  </Card>

  <Card title="firstName / lastName" icon="user" href="/pixel/events/properties/name">
    Customer name for identity resolution.
  </Card>
</CardGroup>