In this article, I will analyze the ways in which Brazilian workers are using social media to organize and mobilize. Although analysis of social media use has made great progress, in the case of worker movements it still needs further development. I will focus on the experience of Brazilian app-based delivery workers during the COVID-19 pandemic. Despite their dispersion across the country, delivery workers were able to carry out two national strikes through intense use of WhatsApp, Facebook, YouTube and Twitter. Using qualitative analysis of posts from worker organizations on social media, it was possible to identify the challenges faced by these movements when using digital media. Social media helped solve some organizational and communication problems, while producing others that workers had to deal with.