1. A method comprising: determining a resource category for a resource based, at least in part, on metadata of the resource; identifying a resource index schema for the resource based, at least in part, on the resource index schema indicating a resource property of the resource; determining, from the metadata, a property value for the resource property; creating an index document that has a format independent of a format of the resource, that indicates the resource property and the property value, and that references the resource in a resource store of heterogeneous native format resources; and storing the index document in an index store that comprises a plurality of index documents, wherein the index document and the plurality of index documents have common formatting.