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

# Link handling

> Control unsubscribe behavior and click tracking on individual links in your email templates.

## Unsubscribe Links

You can designate a link in your email content to generate a `link_unsubscribe` event when clicked using the `data-msys-unsubscribe` custom attribute.

```html theme={null}
<a href="http://www.example.com/unsub_handler?id=1234" data-msys-unsubscribe="1">
  Unsubscribe
</a>
```

<Warning>
  Click tracking must be enabled for the `link_unsubscribe` event to be generated.
</Warning>

## Per-link Disabling of Click Tracking

When click tracking is enabled at the transmission level, you can selectively disable it for individual links using the `data-msys-clicktrack` custom attribute set to `"0"`:

```html theme={null}
<a href="http://www.example.com/" data-msys-clicktrack="0">
  Click here
</a>
```

This is useful when you want click tracking active for most links in your email, but need specific links (such as unsubscribe URLs or legal links) to remain untracked.

### App deep linking

Disabling click tracking on specific links is essential for **app deep links**. Mobile platforms like iOS and Android verify deep links by checking verification files hosted on the link's domain (e.g. `apple-app-site-association` or `assetlinks.json`). When click tracking is enabled, the link is rewritten to go through a tracking domain that doesn't host these verification files, causing the deep link to fail and open in the browser instead of the app.

By adding `data-msys-clicktrack="0"` to your deep links, the original URL is preserved, allowing the operating system to verify the domain and open the link directly in your app.