Handlebar Helper Function: Unless

Conditionally renders a block based on whether a value evaluates to false. This behavior is the inverse of the if helper.

This built-in helper is provided by the Handlebars.Net library.

This helper is available in the Winter ’26 release of Marketing Cloud Next (API version 65.0).

1{{#unless condition}}
2  <!-- Content when condition evaluates to false -->
3{{else}}
4  <!-- Content when condition evaluates to true -->
5{{/unless}}

The function renders the block template if the condition evaluates to false. If an {{else}} block is provided, it renders that block when the condition evaluates to true.

• Github: Handlebars.Net
• Handlebars Language Guide: Built-in Helpers