Conflicts detected during synchronization of replicas are enumerated and resolved according to a specified policy, comprising conditions and actions or simply a specified action. Specified actions may be drawn from a set of standard actions and custom actions may also be composed. The conflicts are enumerated and resolved in logical groups. A logical group is a collection of one or more item envelopes, each comprising entities, such as items, links, and/or extensions. In an example configuration, both constraint-based conflicts, such as a name collision, and non-constraint-based conflicts are handled via the same application programming interface.