Open transport data and the development of mobility applications

Even though open data is no longer a novelty, it raises questions that are far from being resolved by data producers and reusers. This article proposes an immersion in a hackathon organized around the first data sets opened up by a rail transport operator, to understand how they are co-produced by the reusers who integrate them into mobility applications. By combining an ecological approach to social worlds with an ethnography of technical activities, it shows that the originality of this process lies less in the development of applications (as the data producers initially hoped) than in the work of equipping open data with new properties that allow them to be integrated into various information infrastructures. This is achieved through definitions that are shared to a greater or lesser extent, at the crossroads of social worlds whose efforts they help to coordinate around the opening up of new data.