Various examples are directed to systems and methods of executing a web application. A web browser application may receive web application code for executing the web application and service worker code for executing a service worker. The web browser may execute a first portion of the web application code to register the service worker and may execute the service worker. The web application may send a first communication request describing a first recipient computing device. The service worker may determine that the first communication request complies with set of filter rules and send the first communication request to the first recipient computing device.