This article deals with the implementation of an online mediation tool in a pedagogical device intended for English for Special Purposes students in a French university (UPMC). As it is now, it comprises a customized website designed to serve as a guide through the development of the students’ work. This paper will first come back on an experiment aiming at collecting data to define a pedagogical approach supposed to take L2 learners’ needs into consideration. This overview will then be useful in a pedagogical engineering approach to design an online mediation tool. Eventually, the first results concerning the potential of this online mediation model on the second language acquisition process will be given.