An inline diagnostics device was developed to measure the intrinsic shot-to-shot intensity and position fluctuations of the SASE-based LCLS hard X-ray FEL source. The device is based on the detection of back-scattered X-rays from a partially-transmissive thin target using a quadrant X-ray diode array. This intensity and position monitor was tested for the first time with FEL X-rays on the XPP instrument of the LCLS. Performance analyses showed that the relative precision for intensity measurements approached 0.1% and the position sensitivity was better than 5 μm, limited only by the Poisson statistics of the X-rays collected in a single shot.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.