A proxy server automatically includes web applications in web pages at the network level. The proxy server receives, from a client device, a request for a network resource at a domain and is hosted at an origin server. The proxy server retrieves the requested network resource. The retrieved network resource does not include the web applications. The proxy server determines that the web applications are to be installed within the network resource. The proxy server automatically modifies the retrieved network resource to include the web applications. The proxy server transmits a response to the client device that includes the modified network resource. The network resource may remain unchanged at the origin server.