We introduce PhyloJunction, a computational framework designed to facilitate the prototyping, testing, and characterization of evolutionary models. PhyloJunction is distributed as an open-source Python library that can be used to implement a variety of models, through its flexible graphical modeling architecture and dedicated model specification language. Model design and use are exposed to users via command-line and graphical interfaces, which integrate the steps of simulating, summarizing, and visualizing data. This paper describes the features of PhyloJunction – which include, but are not limited to, a general implementation of a popular family of phylogenetic diversification models – and, moving forward, how it may be expanded to not only include new models, but to also become a platform for conducting and teaching statistical learning.