Chemical synapses, although representing the smallest unit of communication between two neurons in the nervous system constitute a complex ensemble of mechanisms. Understanding these mechanisms and the way synaptic transmission occurs is critical for our comprehension of CNS functions in general and learning and memory in particular. Here we describe a modeling platform called EONS (Elementary Object of Neural System) accessible online, which allows neuroscientists throughout the world to study qualitatively, but also quantitatively the relative contributions of diverse mechanisms underlying synaptic efficacy: the relevance of each and every elements that comprise a synapse, the interactions between these components and their subcellular distribution, as well as the influence of synaptic geometry (presynaptic terminal, cleft and postsynaptic density).