Content is dynamically assembled at the edge of the Internet, preferably on content delivery network (CDN) edge servers. A content provider leverages an “edge side include” (ESI) markup language that is used to define Web page fragments for dynamic assembly at the edge. Dynamic assembly improves site performance by caching objects that comprise dynamically-generated pages at the edge of the Internet, close to the end user. Instead of being assembled by an application/web server in a centralized data center, the application/web server sends a page template and content fragments to a CDN edge server where the page is assembled. Each content fragment can have its own cacheability profile to manage the “freshness” of the content. Once a user requests a page, the edge server examines its cache for the included fragments and assembles the page on-the-fly.