Zendesk placeholders, also known as Liquid placeholders or Liquid Markup, are special codes that can be used in Zendesk to dynamically insert data into macros, triggers, automations, and other areas of you Zendesk Support.Placeholders are represented by double curly braces, like this: {{placeholder_name}}, and can be used to pull information from Zendesk ticket, user, and organization fields.

When a placeholder is used in a macro, trigger, automation, or SweetHawk app, it gets replaced with the actual value of the corresponding field or variable when the macro, trigger, or automation is executed. This allows you to create dynamic content that adapts to the specific context its used in.

For example, you could create a trigger that automatically sends a reply to a customer with their name and ticket ID included by using placeholders like {{ticket.requester.name}} and {{ticket.id}}.

Some reasons why you would use placeholders include:

1. Personalization: Placeholders can be used to insert personalized information, such as the customer's name, order number, or account details, into ticket comments or email notifications.

2. Consistency: Placeholders help ensure consistency in ticket responses by providing a standardized way to include certain information, such as a signature or a reference to the customer's previous interactions with your support team.

3. Time-saving: By using placeholders, agents can save time by not having to manually enter information into every ticket or response.

Overall, placeholders are a powerful feature of Zendesk that can help you save time, improve accuracy, and deliver a better customer experience by automatically referencing things to personalize your interactions with customers.

For an overview of common uses for placeholders see here. 

For a full reference of all Zendesk placeholders see here.