Caloric refrigeration and heat pumping play important roles in a potential future substitute for vapour-compression technology. Although caloric refrigeration is foreseen as one of the most promising alternatives, the current low power density of caloric devices represents a serious hurdle to overcome prior to market applications. In order to improve the power density, the number of thermodynamic cycles per unit of time, denoted as the frequency, has to be increased. Thermal switch mechanisms, which act as a control element for the heat flux, represent a promising solution. They can enable the operation of caloric devices at up to an order higher frequencies compared to existing devices and their principles. This review covers the principles of microfluidic mechanisms that can be applied as active thermal switches in caloric technologies. The article can serve as a guideline for the future development of compact caloric devices.