An improved computing system is arranged for cross-origin network communications on a single computing device. The system includes a processor, a networking module, and memory with software instructions arranged to operate a local computing server resource on a first local domain, instantiate a relay mechanism that has an iFrame and an invisible window, instantiate a local web server on a second local domain, install a service worker on the invisible window, receive a request for information at the local web server, verify a presence of the local computing server resource on the first local domain, communicatively connect the second local domain to the iFrame, and directly communicate, via the at least one networking module, at least one message between the local computing server resource on the first local domain and the local web server on the second local domain using the relay mechanism.