Informal waste collectors can provide recycling services to developing cities, while cities seek better data collection and stewardship of their waste systems. Mobile applications can mediate this relationship, but must be accessible and adopted by informal workers. Based on past work with recycling cooperatives in Brazil, we built and tested Forager, a web and mobile platform for coops to track their own collection vehicles in real-time and improve coordination and transparency with their private partners and local government. Through observations, workshops, and interviews, we identified simple, error-tolerant, unobtrusive interfaces as ideal for informal work environments. Finally, we discuss how security, workload, and user expectations present unique opportunities and challenges for pervasive urban applications in developing contexts.