Merger and duplicate resolution for contact information across platforms is managed employing contact objects and aggregating the contact objects into contact models. Contact data from internal and/or external data stores may be retrieved and contact objects created for each contact from each contact store. A contact model for each contact entity may be created by aggregating contact data from contact objects across the contact stores. The aggregation may include duplicate resolution through weighting of communication system types, ranking of contact information type, and similar approaches. The contact models may be dynamically updated based on changes to the contact objects.