‘Listening Back’ is an add-on for the Chrome and Firefox browsers that sonifies internet cookies in real time as one browses online. By translating internet cookies into sound, the ‘Listening Back’ browser add-on provides an audible presence for hidden infrastructures that collect personal and identifying data by storing a file on one’s computer. Addressing the proliferation of ubiquitous online surveillance and the methods by which our information flows are intercepted by mechanisms of automated data collection, ‘Listening Back’ functions to expose real-time digital surveillance and consequently the ways in which our everyday relationships to being surveilled have become normalised. This lecture performance will examine Internet cookies as a significant case study for online surveillance with their invention in 1994 being historically situated at the origins of automated data collection, and the commercialisation of the World Wide Web. I will integrate online browsing to demonstrate the ‘Listening Back’ add-on and explore it’s potential to reveal algorithmic data capture processes that underlie our Web experience.