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Template variables

Template variables are the values that are allowed to change between instances of the same card template. They let one reusable design accept a different entity, label, scale, list, or configuration block without duplicating the complete card.

This page shows how to define placeholders, give them defaults, supply values from a card instance, and pass larger lists or mappings when needed.

Add a variable to a template

Use a descriptive placeholder where the value is needed:

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template:
  type: card
  defaults:
    - name: Temperature  # Name used for this template or supplied value
    - unit: °C  # Unit shown with the value

card:
  entities:
    - entity: "[[entity]]"  # Home Assistant entity used by this card
      name: "[[name]]"  # Name shown to the user
      unit: "[[unit]]"  # Unit shown with the value

A placeholder without a default must be supplied by the card instance.

Supply values when using the template

Template variables let one reusable card structure receive the entity names, text, or other values that differ per use.

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template:
  name: room_temperature  # Name used for this template or supplied value
  variables:
    - entity: sensor.bedroom_temperature  # Home Assistant entity used by this card
    - name: Bedroom  # Name used for this template or supplied value

The default unit remains in use because this instance does not replace it.

Pass a list or configuration block

A variable can also contain a list or map:

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template:
  name: room_overview  # Name used for this template or supplied value
  variables:
    - rooms:
        - Living room
        - Bedroom
        - Study

Use variables only for differences between instances

Use a variable when the value is supplied when the card is created. Use a JavaScript template when the value should change later with an entity state.