The user picker method (
/rest/api/3/user/picker) doesn’t currently support the ability to filter out JSM customer users (
accountType='customer'). There is a feature request that we’d like to measure interest in: a new exclusion filter that operates similarly to the
excludeConnectUsers parameter, in that it would exclude JSM customer accounts.
If this is of interest to you, please visit the feature request ticket above to vote / comment.