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

# Custom Headers

> Pass custom metadata with outbound messages.

Custom headers allow you to attach metadata to outbound requests for tracking, routing, or downstream processing in your n8n workflows.

```json theme={null}
{
  "to": "user@example.com",
  "headers": {
    "X-Client-ID": "client_123",
    "X-Campaign": "q2-outreach"
  }
}
```