# Supported API headers
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Infobip Email API supports standard and custom headers to improve delivery and compliance.

| Header           | Description                                               |
|------------------|----------------------------------------------------------|
| `List-Unsubscribe` | Required for compliance. Adds unsubscribe link or email address. |
| `Reply-To`         | Defines reply-to address.                               |
| `Return-Path`      | Handles bounces and delivery failures.                  |
| `Message-ID`       | Custom unique ID for tracking.                          |
| `X-Custom-*`       | Add your own custom headers for integration needs.      |

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