The rise of work mediated by digital platforms has profoundly reconfigured the work experience, imposing new forms of fragmentation, precariousness, and control of the working class. In the Brazilian context, app delivery workers face algorithmic management as a mechanism that intensifies individualisation, hinders communication between workers, and weakens traditional solidarity practices. Given this scenario, this article focuses on investigating how delivery workers resist the isolation imposed by algorithms and build collective forms of organisation and mobilisation, paving the way for a union reconstruction adapted to the realities of digital work. The research adopts a qualitative methodology, combining documentary analysis of public demonstrations, especially in Brazil, materials from unions and delivery workers' collectives, with semi-structured interviews conducted with union leaders, members of autonomous associations, and workers involved in recent strikes. Interactions on digital networks, such as WhatsApp groups and social media profiles focused on labour mobilisation, were also observed. Preliminary results indicate that, although algorithmic fragmentation poses significant obstacles, new forms of solidarity are emerging in the daily lives of delivery workers. Resistance strategies include self-organised strikes, public denunciation campaigns against platforms, digital support networks, and the creation of category-specific associations, such as the National Alliance of App Delivery Workers (ANEA). The collective resistance practices analysed are characterised by a strong horizontal, flexible, and connected component, challenging traditional union models and demanding institutional innovations to represent workers in the platform economy. The article argues that the algorithmic resistance of Brazilian delivery workers reveals both limits and possibilities for the future of collective organisation in digital work. The research contributes to the international debate on the capacity of platform workers to organise in contexts of high precariousness and intense technological surveillance. In addition, it proposes reflections on the role of the union system in Brazil in the face of the platformization of work, highlighting the need to revisit organisational strategies, legal frameworks, and representation models. By analysing the trajectory "from fragmentation to collectivity" of app delivery workers, the study illuminates emerging practices of resistance that strain the boundaries between autonomous and subordinate work, individualism and solidarity, precariousness and collective emancipation in the digital age.