The described technology is directed towards a data transformation pipeline architecture of a data service that processes generalized datasets into datasets (e.g., video data or graph nodes) customized for a particular client device. Described herein is maintaining a set of data transformation models at a data service, and upon receiving a client request for data, selecting a relevant subset of the transformation models and arranging the subset into a data transformation pipeline. In general, the pipeline of transformation models transforms the generalized data into the format and shape that each client device expects. The subset may be selected based upon device type, device class and/or software version information (and possibly state data) sent with each data request. The transformation models may be maintained in a hierarchical data store such as files in a file system to facilitate retrieval by searching the hierarchy for appropriate transformation models.