Heart disease is the number one cause of death in the US (Xu et al., 2020). Many efforts have been devoted to studying its progression, diagnosis, and treatment. During the past decade, computational modeling has made significant inroads into the research of heart disease. The heart is inherently a multiphysics system that includes electrophysiology, tissue mechanics, and blood dynamics. Its normal function starts with the propagation of electrical signals that trigger the active contraction of the heart muscle to pump blood into the circulatory system. Rooted in fundamental laws of physics such as the balance of mass, momentum, and energy, computational modeling has been instrumental in studying cardiac physiology such as left ventricular function (Mittal et al., 2015), cardiac arrhythmia (Trayanova, 2011), and blood flow in the cardiovascular system (Arzani & Shadden, 2018;Grande Gutiérrez et al., 2021). svFSI is the first open source software that specializes in enabling coupled electro-mechano-hemodynamic simulations of the heart.