We describe a new type of operando Fourier transform infrared (FTIR)-mass spectrometry setup for surface-chemical and reactivity characterization of heterogeneous catalysts. On the basis of a sophisticated all-quartz FTIR reactor cell, capable of operating between room temperature and 1000 °C in reactive gas atmospheres, the setup offers a unique opportunity to simultaneously collect and accordingly correlate FTIR surface-chemical adsorption data of the active catalyst state and FTIR gas phase data with complementary reactivity data obtained via mass spectrometry in situ. The full set of catalytic operation modes (recirculating static and flow reactor conditions) is accessible and can be complemented with a variety of temperature-programmed reaction modes or thermal desorption. Due to the unique transfer process involving a home-built portable glovebox to avoid air exposure, a variety of complementary quasi in situ characterization methods for the pre- and post-reaction catalyst states become accessible. We exemplify the capabilities for additional x-ray photoelectron spectroscopy characterization of surface-chemical states, highlighting the unique strength of combining adsorption, electronic structure, and reactivity data to gain detailed insight into the reactive state of a Cu/ZrO2 heterogeneous catalyst during methanol steam reforming operation.