Talk description: During the 2018 Brazilian general election, WhatsApp became a potent tool for the spread of misinformation, especially for supporters of Bolsonaro. I began monitoring pro-Bolsonaro WhatsApp groups in March 2018- at the outset of the election, the social media app eventually helped Bolsonaro win and become the president of Brazil. I found that fake news spread in typical fashion, through a structure of groups that resembled a pyramid. Now, ten months into Bolsonaro’s presidency, WhatsApp is still serving as a largely hidden platform for the radicalization of right-wing Brazilians, even as Bolsonaro’s once-united base has splintered into separate, and often competing, factions. In this talk, I uncover hidden spaces of populism and misinformation on WhatsApp and detail the social infrastructure that is radicalizing the right in Brazil.