PurposeThe purpose of this paper is to consider Mexico City’s street markets as temporary and modular architectural products that emerge out of intensive, routine and repeated negotiations over urban spatial affordances in a crowded metropolitan environment. Particular attention is given to the polychromatic visual form, not as some detached work of art, but as a collection of tiny signals of the labor, commerce and social relations unfolding below.Design/methodology/approachFor this paper, the author has deployed a methodological approach that blends scholarship and creative practice. From 2016 to 2018, the author conducted fieldwork during three trips to Mexico City, making site visits, undertaking structured observation and engaging in conversations with vendors and customers. The author also collected data available from various municipal agencies, and reportage from newspaper articles, blogs and magazines. Meanwhile, the author developed a creative practice method grounded in the production of rendered aerial views, which allowed for the identification of typologies based on the organizational logics of the street markets.FindingsThe paper identifies five typologies of street market, including: the linear, the circuit, the cluster, the contour and the hybrid. The application of these typologies by street market vendors allows for the optimal exploitation of spatial allotments for buying and selling goods. In the end, the paper reveals the polychromatic markets as expressions of an assemblage aesthetic, each a variation on a theme grounded in the cumulative daily choices, desires, routines and thickly woven collaborations of working-class people in one of the world’s great conurbations.Research limitations/implicationsThe study is based on a limited number of cases. There are currently 1,400 street markets regularly operating in Mexico City, 200 of which set up on any given day. In order to provide some depth and texture to the study, this paper only examines 15 markets falling into the five typologies identified above. Further research would help to refine these typologies, quantify the daily and quarterly transactions that take place in the markets and assess the impacts of street vending on their surroundings.Social implicationsMexico City’s street markets provide employment for some 800,000 vendors, suppliers, transporters and laborers. They also provide one-fifth of all household goods purchased in the city and 40 percent of all fresh produce. And despite the conflicts that arise, they offer an associational approach to the labor of street vending, as well as crucial economic opportunities for women with children. However, it is apparent that street markets face a range of challenges that could be mitigated with supportive policies.Originality/valueWhile there is a small and growing literature on Mexico City’s street markets, there is no work to date that examines the assemblage aesthetic that comprises their daily emergence on the landscape. Nor do any extant studies situate the aesthetic composition within the varied urban forms, social relations and labor practices that undergird the street markets.