Résumé : This article examines a delivery workers’ strike in Brussels that, for the first time, brought together undocumented couriers and trade unions. It explores the impact of platform labor on widening inequalities in both the labor market and collective representation. We argue that the platform model has contributed to a growing disconnect between trade unions and undocumented workers – individuals who are already underrepresented. Drawing on participant observation and semi-structured interviews with union representatives and mobilized couriers, we analyze the conflicting interests generated by platform work, particularly the tension between the formal wage-based model promoted by unions and the informal working conditions experienced by couriers.