LUSID automatically generates a unique ID for every user, whether personal or service.
You may need to know a user's ID to perform a particular operation, for example setting up an automated activity on behalf of a service user, or filtering entities created or modified by a particular user.
Assuming you have appropriate permissions, you can discover user IDs by navigating to the Identity and Access > Users dashboard in the LUSID web app:
Alternatively, you can call the ListUsers API:
Conversely, if you know a user's ID and want to discover more information about them, call the FindUsersById API.