You don’t have to send users to LaunchDarkly in advance – just set up your users in
variation calls and you’re all set: http://docs.launchdarkly.com/docs/getting-started .
If we do not receive a request for a user in 30 days, then that user will no longer appear in the dashboard, but will still be stored in the database. If we detect that the user is active again, then they will reappear in the dashboard with the latest set of attributes. You cannot remove users manually from the dashboard.
You may add individual users using the LaunchDarkly dashboard by navigating to a feature flag and adding users manually in the targeting tab.