Attributes are different characteristics associated with your visitors (for example, demographics, behavior, etc.).
If you want to target anything that isn’t available by default, you can use custom attributes to store and retrieve data about your visitors. Once a custom attribute is defined and set on a page visit, you can leverage it to define a rules-based audience or filter optimization results by the attribute.
Custom attributes are first defined in Webflow Optimize, and then set for a user or pageview by using the wf.setAttributes() method of the Browser API. By setting an attribute, you’re sending data to Webflow Optimize that can be used to create a rules-based audience or filter optimization results.
If you have an enterprise site, navigate to the Insights tab on your site and click Integrations. Find the Custom JavaScript attributes section and create a new entry.

This method is only available on enterprise sites.
Once configured, you can set custom attributes when a user visits your site by using wf.setAttributes(). See the example below, and the documentation for more details.
Custom attributes can be set for a specific scope, which determines the lifetime of the attribute.
Example:
Once you’ve created and set a custom attribute, you can use it to create a rules-based audience or filter optimization results.
Create a rules-based audience to target visitors based on their custom attributes.
Filter optimization results by custom attributes.
Visit the Webflow Help Center to learn more about custom attributes and audiences in Webflow Optimize, including:
You can also explore Webflow University for additional tutorials and resources on making the most of Webflow Optimize’s personalization features.