Dérive is a mobile application designed to encourage exploratory walking through cities using playful prompts and chance-based instructions. Inspired by the Situationist concept of the dérive, a method of drifting through urban environments to experience their psychological and social effects, the app nudges users to move through places in unfamiliar ways rather than following conventional routes. Instead of maps or predefined routes, the app presents users with “task cards” that propose actions, observations, or small interventions in the surrounding environment. These prompts might ask users to follow a particular sound, look for overlooked details, interact with strangers, or reinterpret the built landscape. By introducing randomness and curiosity into walking, the app transforms everyday urban movement into a creative and reflective practice that reveals hidden histories, spatial patterns, and social dynamics. Dérive is used by artists, educators, and curious pedestrians alike to explore cities from new perspectives. It functions both as a personal exploration tool and as a platform for curated “decks” of task cards created by artists, researchers, or communities. Through these decks, the app supports workshops, participatory art projects, and psychogeographic experiments that invite participants to question how cities are structured and how people move through them.