US Patent 9509764 Updating cached web content

Updating cached data is disclosed. An indication that a web content has been updated is received. An updated version of the web content is received. A difference between the updated version of the web content and a previous version of the updated web content is determined. A request for the updated version of the web content is received from a client. The difference in place of the updated version of the web content is provided to the client. The client generates the updated version of the web content using the difference and the previous version of the updated web content cached by the client.