Approach for versioning of documents is described. A version accumulator structure stores one or more version values indicating different versions of a data object. The data object is decomposable into a plurality of nodes. One or more copies of each node of the plurality of nodes are stored, where the one or more copies are associated with non-overlapping version ranges. A first request to perform a change to the data object is received. The first request specifies an effective version value for the change, which involves a particular node. The change is performed based on the effective version value and without making a deep copy of the data object. A second request to retrieve a certain version of the data object is received. The certain version is retrieved based on the version ranges associated with the one or more copies of each node of the plurality of nodes.