Fluxer is a web application for the computation and interactive visualization of flux graphs from genome-scale metabolic models. Flux Balance Analysis is used to calculate the flux of the metabolic network, which can then be visualized with spanning trees, k-shortest paths, and complete graphs. More than 80 genome-scale metabolic networks are currently pre-loaded in the application and available for visualization. In addition, any user can upload their own SBML metabolic models for Fluxer to compute, analyze, and visualize their flux graphs. Any generated graph can be downloaded as a high-quality image.