Abstract This article addresses the role of new technologies in the international justice and accountability landscape, drawing from research we conducted into new United Nations (UN) accountability mechanisms that have the explicit mandate to collect, collate, analyse and preserve evidence of international crimes according to criminal justice standards. The article is divided in four parts. First, we contextualize our research by discussing some of our findings and situating them against what we define as a ‘third wave’ of institutional developments in international justice, prompted by an ‘accountability-turn’ affecting civil society groups and UN mandates. Secondly, we discuss — using real-world examples — both the opportunities and challenges arising from the use of digital and new documentation technologies in the field. Thirdly, the article pays particular attention to the role of UN mandates affected by the ‘accountability-turn’; our research reveals such UN mandates now often sit at the heart of the ‘life cycle’ of information and evidence collected for justice and accountability purposes. In this section of the article, we also briefly discuss issues relating to third party control of information, in particular by social media companies. Finally, we discuss the need (and welcome initiative) to develop better international guidance and best practices for actors across the board in order to maximize the effective use of new technologies and digital evidence in international justice and accountability processes.