...

The importer supports syncing devices based on Role, Tag, Location or Custom field.

NetBoximporter NetBox importer supports remote UUIDs.

How to configure the importer

...

3) Configure Role, Tag, Location or Custom field, to import devices from, one per line.
 Device Device group must be configured in key value format e.g.  "role= Switch", “"tag=TagName”TagName", "location=Server room racks", "field=FieldName:FieldValue" (without quotes).
Values in NetBox are case-sensitive, which is why it is necessary to use the exact same format of the value as stored in NetBox.

Please be aware that for use of Custom field is necessary to specify custom field name (in NetBox it can be found directly in custom field section) NOT a label which is displayed in NetBox UI  in case is filled up under the custom field. Label UI. 
The label is currently not supported by the NetBox API that , which is why no results can be expected for import by using this parameter can be expected. 

4) Optionally, you can also schedule the importer.
 You simply need to select an existing (or use the default) schedule.
 With this configuration, Unimus will sync against NetBox periodically.

...