Communications technologies are being used in varying ways to perpetrate and extend the harm of sexual violence and harassment against women and girls. Yet little scholarship has explored the uses of communications technologies, to support reporting, investigation and prosecution of sexual assault, nor indeed less formal mechanisms of justice. In this article, I contend that communications technologies are not simply new tools for conventional formal justice, but rather that these technologies are mediating new mechanisms of informal justice outside of the state, in turn challenging meanings of justice in western liberal democracies. In so doing I employ concepts of technosocial practices operating in counter-public online spaces, to explore the potential (and limits) of communications technologies as mediators of rape justice.