Zeta Markup Language (ZML)

Input

{{ first_name }}

Output

Ryan

Input

{% if first_name %}

Hello {{ first_name }}!

{% endif %}

Output

Hello Ryan!

Input

{{ first_name | default: "Valued Customer" }}

Assuming first_name is null or doesn't exist:

Output

Valued Customer

Input

{{ "ryan!" | capitalize | prepend: "Hello " }}

Output

Hello Ryan!

Use Single Quotes for String Values in Global Variables

When assigning string values with the global tag, use single quotes:

{% global displayed = 'store' %}

Using double quotes can produce unexpected output because the double quote may be treated as part of the stored value:

{% global displayed = "store" %}

This can result in output such as:

"store

For this reason, string values assigned with global should always use single quotes.

Global and Assign Have Different Scope, Not Different String Parsing

Both global and assign are used to create variables, but they serve different purposes:

{% assign displayed = 'store' %}

creates a variable that is available only within the current component or template scope.

{% global displayed = 'store' %}

creates a variable that can be referenced across message components such as the subject line, preheader, and content.

The primary difference is scope, not how string values are parsed.

Global Variables Do Not Support Filters

Unlike assign, the global tag does not evaluate filters when assigning values.

For example:

{% assign first_name_upper = first_name | upcase %}

stores the transformed value.

However:

{% global first_name_upper = first_name | upcase %}

stores the literal text:

first_name | upcase

instead of the filtered result.

If a value requires filters, apply the filter using assign or directly in the output expression.

When to Use Global vs Assign

Use global when a variable must be shared across multiple message components via the Global Variables field.

Use assign when the variable is only needed within a single content block or template.

Snippets in the Global Variables field must use the global tag to be available throughout the message. The assign tag creates locally scoped variables and will not make values available across components.

Campaigns include a standalone Global Variables field that allows you to define variables that can be referenced across all message components, including the subject line, preheader, and content.

Use the global tag when a variable needs to be shared across multiple message components:

{% global my_var = 'value' %}

Use the assign tag when a variable is only needed within a single component:

{% assign my_var = 'value' %}

Snippets placed in the Global Variables field must use the global tag to make variables available throughout the message. Variables created with assign are scoped locally and are not available outside the component in which they are evaluated.