We have designed and constructed a compact spectrometer dedicated to in-situ characterization of thin films during deposition, using soft x-ray emission spectroscopy. It consists of a Rowland-circle mounted spherical grating and entrance slit, or slit array to enhance throughput. A 2D position-sensitive detector (microchannel plate stack and resistive anode) is mounted tangent to the image of the slit(s) on the Rowland circle. The instrument covers an energy range of 240 - 700 eV using a 300 1/mm grating in the first order. Thus, the spectrometer simultaneously records K emission for low-Z elements C through F, while L emission for 3D metals can be recorded in first or higher orders. The resolution is approximately 300, allowing chemical analysis. Both detector and grating are housed in a vacuum chamber that is turbomolecularly pumped to a pressure below 10-6 Torr. The instrument can be attached to any process chamber using a standard UHV flange. The slit extends into the process chamber separated from the housing by a valve. This valve can be closed, or in one of two open positions where thin foils serve as vacuum windows to protect the detector and grating, and as filters to reduce background counts from UV light. The spectrometer has successfully monitored a variety of processes in situ, including growth of optical TiN films by reactive magnetron sputter deposition, synchrotron radiation induced CVD of metallic films, and hot-filament CVD growth of diamond.