There is no option to add 7Mode filer to oncommand API Server. Oncommand API Services is designed for Clustered Ontap Storage Systems.
Overview of OnCommand API Services
As you plan your installation and setup of OnCommand API Services, you might find it useful to read an overview of how OnCommand API Services, Unified Manager, and Performance Manager interact to enable monitoring and management operations of clustered Data ONTAP storage systems, from partner applications.
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