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Optimizely Knowledge Base

Migrating from uploaded audiences to list attributes

relevant products:
  • Optimizely X Web Experimentation
  • Optimizely X Web Personalization
  • Optimizely Classic

  • Understand the migration from uploaded audiences to list attributes
  • Build and implement your own list attributes 

Uploaded audiences is an Optimizely Classic feature that enables you to target visitors based on their membership in an audience you've already defined somewhere outside of Optimizely. With this feature, you import custom list of users and then create audience conditions based on those lists.

List attributes is the Optimizely X version of uploaded audiences. List attributes support all the same functionality as uploaded audiences. They also provide some significant performance improvements.

Benefits of List Attributes


Uploaded Audiences

Lists Attributes

Data upload methods

In-browser, REST API

In-browser, REST API, Amazon S3

List size limit


Unlimited (when uploading via Amazon S3)

Ingest speed (time between data upload and availability of data for targeting)

Up to 4 hours

Up to 1 hour, and typically much faster

Management interface

Optimizely Classic

Optimizely X

While the list attributes management interface is only available in Optimizely X, once a list has been configured, you can also use it to target Optimizely Classic experiments.

Migrating from uploaded audiences to list attributes

Optimizely X automatically recreates any uploaded audiences created in Optimizely Classic as list attributes. It also converts any audiences that referenced uploaded audience conditions to use list attributes conditions instead. This means that any existing audiences which use uploaded audiences will continue to work as before, and any active experiments or campaigns will continue to operate as expected.

Management interface

The management interface is where you create, modify and archive lists in the Optimizely web application. With Optimizely Classic, this was found on the Uploaded Lists tab in the project overview. In Optimizely X, the interface can be found on the Attributes tab within the Audiences dashboard.


Any uploaded audiences which were previously created in this project will now appear as list attributes in this new interface.

For more information on how to use the new list attributes interface, please visit this how-to guide.

Audience builder

The audience builder is where you go to create Optimizely audiences. In the past, you would find the uploaded audiences condition under the list of standard conditions.


With Optimizely X, you can find list attributes under the External Attributes heading:


You can always search for a specific list using the Browse by Name search box above the conditions list.