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

> ## Agent Instructions
> Automate.ax automations are TypeScript programs.
> Use Bun for installation and command examples.
> Use Automate.ax for the product name and automate.ax for the package, CLI, and domain.
> Treat documented public APIs as current; do not invent transitional or deprecated names.

# Update contact property

> Update a Resend contact property's fallback.

`resend.updateContactProperty` update a Resend contact property's fallback.

```ts automations/resend-updateContactProperty.automation.ts theme={null}
import { automation } from "automate.ax"
import { resend } from "automate.ax/resend"

export default automation("Update contact property", () => {
  resend.updateContactProperty({
    propertyId: "property_123",
    fallbackValue: null,
  })
})
```

`fallbackValue` accepts a string, number, or null to clear it. A non-null value must match the property's existing type. Optional second argument `{ account }` selects the Resend account binding.