A near end network optimizer receives, from a client device, a request for a network resource. Responsive to determining that a version of the network resource is stored in the near end network optimizer, a request for the network resource is transmitted to a far end network optimizer along with a version identifier that identifies that version. The near end network optimizer receives, from the far end network optimizer, a response that includes a differences file that specifies the difference(s) between the version of the network resource stored in the near end network optimizer with a most current version of the network resource. The response does not include the entire network resource. The near end network optimizer applies the specified difference(s) to the version that it has stored to generate an updated version of the network resource, and transmits the updated version of the network resource to the client device.