In one embodiment, a method includes receiving a request for a web page, sending a first response portion for generating the requested web page to a client computing device that includes a structured document including a page-assembling process, generating one or more second response portions each for generating a corresponding portion of the requested web page that each include a call to the page-assembling process, transmitting the second response portions to the client computing device, and wherein the page-assembling process is configured to, responsive to a call corresponding to a respective second response portion, insert, or cause to be inserted, content, resources, or calls to resources included in the respective second response portion into a model representation of the structured document generated by a client rendering application at a location in the model representation determined by a corresponding place-holder code segment included in the structured document.