You can use the SKIM APIs. Endpoint: https://docs.databricks.com/dev-tools/api/latest/scim/scim-users.html#get-users

Or you can use the Workspace API. The workspace API does not have a direct list users command, but you can use the workspace API to list all the folders in the "Users" directory, filter the results to only have directories with the "@" symbol. Endpoint: https://docs.databricks.com/dev-tools/api/latest/workspace.html#list