Providing an introduction to the special section ‘Close encounters: ethnographies of the coproduction of space by the urban poor’, this article sets out to argue that the image of ‘the informal’ as unruly, messy and dirty continues to inform urban planning around the world. As a reaction to this view, it contends that the informal and formal should be analysed as interconnected and that the informal sphere should be revalued. Urban development is studied as close encounters between established practices, with a locus and a history (tree‐like), and newly emerging, unstable and untraceable practices (rhizomatic). Contrary to the tendency in urban planning to conflate the formal with the tree and the informal with the rhizome, we argue that from the perspective of marginal urbanites, formal planning tends to be very arbitrary and frightening (rhizomatic), whereas informal practices can be very predictable and stable (arboreal). The article analyses residents of marginalized urban areas as inventive navigators who explore the changing physical, spatial and sociopolitical environment, avoiding threats and looking for opportunities, grounded in their everyday practices and life histories. The article concludes that marginal urbanites should be acknowledged as coproducers of urban space and that the right to ‘coproduce’ the city lies at the heart of the call for the right to the city.