curl -u admin:admin -X POST http://localhost:9000/api/lists -H 'Content-Type: application/json' -d '{"name":"Product Updates","type":"public","optin":"double"}'

Creates a list; name, type, and optin are required fields. type public makes it appear on subscription forms while private hides it, and optin double sends a confirmation email that new subscribers must click before they receive campaigns. The response contains the new list id for later calls.