We introduce RuleBender, a novel visualization system for the integrated visualization, modeling and simulation of rule-based intracellular biochemistry. Rule-based modeling (RBM) is a powerful and increasingly popular approach to modeling cell signaling networks. However, novel visual tools are needed in order to make RBM accessible to a broad range of users, to make specification of models less error prone, and to improve workflows. We present the user requirements, visual paradigms, algorithms and design decisions behind RuleBender, with particular emphasis on visual global/local model exploration and integrated execution of simulations. The support of RBM creation, debugging, and interactive visualization expedites the RBM learning process and reduces model construction time; while built-in model simulation and analysis with multiple linked views streamline the execution and analysis of newly created models and generated networks. A development cycle that includes close interaction with expert users allows RuleBender to better serve the needs of the systems biology community.