Socialgraph and Gizmoduck were two of the largest and most critical backend services at Twitter. It was a pleasure to help maintain and develop on top of them. Maintaining the infrastructure and lifecycle for these systems involved on-call and incident management of our servers for user data and graph data.
I built frameworks and systems to serve and manage User Graph data (Follows, Block, etc), including an Entity Lifecycle system that allowed data to react to User Lifecycle changes such as suspension and deactivation.