One embodiment of a guest browser system, among others, includes a guest browser interface configured to provide an address bar interface for accepting a network address for retrieving a first web page. The guest browser interface is rendered from code of a second web page, where content of the second web page is rendered by an installed web browser. The system further includes a guest browser engine configured to retrieve contents of web pages. The guest browser engine is built from code provided by the second web page and is used to update content of the second web page with content from the first web page. Other systems and methods are also provided.