When will Cognito User Pool custom attributes be indexed for searching and filtering?

Workarounds and Considerations:

Use of Standard Attributes:

As you mentioned, repurposing unused standard attributes (OIDC claims) is one potential workaround. However, this approach can lead to issues if those attributes are needed in the future for their intended purposes.

Client-Side Filtering:

Another approach is to retrieve all users and filter them on the client-side. While this method can work for smaller user pools, it can have significant performance implications as the number of users grows. Additionally, this method may expose unnecessary data to the client, which can be a security risk.

Custom Database or Data Store:

A more scalable and secure approach would be to maintain a separate database or data store where you store the users' information, including custom attributes. You can then perform more complex queries and filtering operations using this database. This adds some complexity to your architecture but provides more flexibility.

Cognito Roadmap:

As of my last update, there is no public information available regarding when or if Cognito will support indexing custom attributes for searching and filtering. AWS often updates its services based on customer feedback, so keeping an eye on the AWS forums, release notes, or directly engaging with AWS support might provide updates on this feature.

https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html