Create a Public Property for a Flexcard LWC in the Flexcard Designer

In the Flexcard Designer, define an attribute that creates a public property whose value is set in the Lightning App Builder and Experience Builder. Call the attribute within the Flexcard as a session variable ({Session.AttName}) where merge fields are supported, such as in a Text element and a data source parameter.

For example, enable an admin to limit the number of records displayed on a Flexcard on a record page. Enter the session variable in a SOQL query, such as where Limit = {Session.RecordLimit}.

Public properties are published to the configuration file that defines the metadata values for your Flexcard LWC. See targetConfig > property in Configuration File Tags. Additional metadata values are configurable in the Designer with the Publish Options feature when your card is active. See Publish a Flexcard.

Required Versions
Available beginning Winter '22.

One public property you can define is the Flexcard's ContextId. See Access the ContextId of a Flexcard on an Experience Site.

In the Flexcard Designer, select Setup to open the Setup panel.
Click + Add New next to Exposed Attributes, and enter the values for the following properties:
- Attribute: The name of the attribute in PascalCase, such as RecordLimit.
  
  Important
  The generated API name is cfPropName. From a Custom LWC or an Omniscript, reference the property name in kebab case, such as cf-record-limit.
- Type: Select the type of property from the dropdown:
  - Select String to display a text field whose value must be text.
  - Select Boolean to display a checkbox that evaluates to true when checked and false when not checked.
  - Select Number to display a text field whose value must be a number.
- Targets: Select one or more page types for which this property is visible.
  
  Note
  To view the property in an Experience Builder site, select lightningCommunity__Default.
- Label: Enter the property label, such as Record Limit.
- (Optional) Value: Enter a default value.
Click Save.
To call the attribute as a session variable within the Flexcard, use the {Session} merge field. For example, if your Attribute name is RecordLimit, enter {Session.RecordLimit}.
Use {Session.RecordLimit} in fields where merge fields are supported. Examples are a Text element, a data source's test and input parameters, and a Field element's Output property.
Activate your Flexcard.
To configure where your Flexcard can be published, such as a Lightning page or an Experience Builder site, see Define Metadata Values from the Flexcard Designer.
To add your active Flexcard to a Lightning or Experience page, see Activate and Publish a Flexcard.
To configure the public property in the Lightning App Builder or Experience Builder, update the value of the property in the Builder's properties panel.

Note
Beginning Summer '22, if you add a standard Flexcard component to a Lightning or Experience page, enter the public property as a JSON key/value pair in Exposed Variables. For example, if the Label of your exposed attribute is RecordLimit, enter {"RecordLimit": 20}. To configure multiple variables, enter a comma-separated list of key/value pairs, such as {"RecordLimit": 20, "Greeting": "Hello"}.