1. A computer implemented method comprising: receiving, by a data communication server computer and from a client computational device, a request for a plurality of external data objects, wherein the data communication server computer comprises a container data object with a reference to the plurality of external data objects, wherein the request comprises a client-side entity tag uniquely identifying a first version of a bundle, and wherein the first version of the bundle comprises the plurality of external data objects and is stored in a temporary memory location in the client computational device; determining, by the data communication server computer, whether the client-side entity tag is associated with a server entity tag; and in response to the client-side entity tag being associated with the server entity tag: transmitting, by the data communication server computer, a response indicating that the bundle may be retrieved from the client computational device; otherwise in response to the client-side entity tag not being associated with the server entity tag: retrieving, by the data communication server computer, the plurality of external data objects from a database; performing, by the data communication server computer, a first level compression on the plurality of external data objects; creating, by the data communication server computer, a second version of the bundle comprising the plurality of external data objects; performing, by the data communication server computer, a second level compression on the second version of the bundle; and transmitting, by the data communication server computer, a response comprising the second version of the bundle to the client computational device, wherein the response comprises the server entity tag and a status code indicating a valid status of the server entity tag, wherein the server entity tag uniquely identifies the second version of the bundle.