Can I add a user to only the Sandbox in the Console?

A user can only be added to both the Sandbox and Live environments.

This is the expected behavior, but we are actively reviewing and gathering feedback on how our clients use the Console, and changes may be made in the future.

If you need to keep Sandbox and Live users separate, you’ll need to create two separate apps—one dedicated solely to the Sandbox environment and the other to the Live environment. This will allow you to keep the users completely isolated in each environment.