In recent years, reports and anecdotal evidence pointing at the role of WhatsApp in a variety of events, ranging from elections to collective violence, have emerged (Arun, 2019). While academic research should examine the validity of these claims, obtaining WhatsApp data for research is notably challenging, contrasting with the relative abundance of data from platforms like Facebook and Twitter, where user “information diets" have been extensively studied (Barberá et al., 2015; Guess, Nagler and Tucker, 2019). This lack of data is particularly problematic since misinformation and hate speech are major concerns in the set of Global South countries in which WhatsApp dominates the market for messaging (Tucker et al., 2018). To help make research on these questions, and more generally research on WhatsApp, possible, this paper introduces WhatsApp Explorer, a tool designed to enable WhatsApp data collection on a large scale. We discuss protocols for data collection, including potential sampling approaches, and explain why our tool (and adjoining protocol) arguably allow researchers to collect WhatsApp data in an ethical and legal manner, at scale.