Variables

Variables allow DTPR elements to be customized when they are deployed in a specific datachain instance. They enable reusable element templates that can be tailored to individual use cases.

How variables work

Variables are defined at two levels:

1. Element-level variables — Defined in the element's variables array
2. Category-level variables — Defined in the category's element_variables array and inherited by all elements in that category

Each variable has:

• id — A unique identifier (e.g., additional_description, duration)
• required — Whether the variable must be provided when deploying the element
• label — A localized label for the variable (locale array format)

Variable interpolation

Element descriptions can reference variables using double curly brace syntax:

{
  "description": [
    {
      "locale": "en",
      "value": "This system stores data for {{duration}} and {{additional_description}}"
    }
  ]
}

When an element is instantiated in a datachain, the variable placeholders are replaced with the instance-specific values.

Instance variable values

When deploying an element in a datachain, variable values are provided in the instance:

{
  "instance": {
    "priority": 0,
    "variables": {
      "additional_description": [
        {
          "locale": "en",
          "value": "This technology can also capture audio data."
        }
      ],
      "duration": [
        {
          "locale": "en",
          "value": "30 days"
        }
      ]
    }
  }
}

Variable values for user-facing text follow the same locale array format as other DTPR content, enabling per-language customization.

Category-inherited variables

Categories can define variables that are available to all elements within that category. For example, a retention category might define a duration variable that every retention element can use.

These category-level variables appear in the element's variables array in API responses, merged with any element-specific variables.