Cell–cell fusion is a highly regulated and dramatic cellular event which is key to cell development. Reverse micelles (RMs) consist of nanoscopic droplets of water delimited by a dynamic, but well-defined surfactant layer, which confers them the status of simplified mimics of cells. Here, we have used anionic and cationic reverse micelles as mimetic environments of a cell, and monitored their fusion in a microfluidic channel via time-resolved evolution of chemiluminescence resulting from the fusion of reverse micelles. As the intracellular environment is highly crowded compared to relatively dilute in vitro conditions, we have also monitored time-resolved chemiluminescence resulting from the fusion of reverse micelles containing a model crowding agent PEG1000 in their aqueous core. Inter-micellar attractive interactions and surfactant film flexibility around the aqueous core of the reverse micelles dictate the kinetic pathways of their fusion.