An in situ diffraction platform for serial crystallography at room temperature. A micrograph of bacteriophytochrome crystals grown on the device is shown on the right. These crystals and the entire device can be mounted on an APS beamline directly for diffraction experiments. As shown in the inset, an x-ray beam through the monocrystalline device substrate will not cause any interfering Bragg diffraction or diffuse scattering. A diffraction image on the left shows very clean data from protein diffraction only.