What filtering syntax to use in headless API for filtering for those entries that do not belong to any categories?

Issue

• I am using the API GET /v1.0/asset-libraries/{assetLibraryId}/content-elements, but the question might be relevant for other endpoints as well
• according to https://learn.liferay.com/w/dxp/low-code/objects/understanding-object-integrations/using-custom-object-apis/object-api-basics , at the time of writing this article (August 2025) there is this example syntax given for saying something like "give me back those entries that belong to this or that category"

taxonomyCategoryIds/any(k:k in (1234,5678))

However, there is no example for what syntax should be used if I want to say "give me back those entries that do not belong to any category". How can I do that?

 

Environment

• QR

Resolution

• syntax

 not taxonomyCategoryIds/any(k:k ne null)

 

should work. Please also make sure that you use public vocabularies, it might not work otherwise.

• for object API's (currently), the syntax 

not taxonomyCategoryIds/any()

 

should also work.