X-ray imaging is a key component of applications ranging from medicine and food to security and industrial non-destructive testing (NDT). Current approaches to X-ray detection however are limited with respect to shape flexibility and material cost. Inherent inflexibility of the digital electronics and scintillating materials used both in charge integrating and particle counting detectors leads to inaccurate imaging of complex geometries due to geometric magnification. This is particularly problematic in industrial NDT where defects in complex shapes are easy to miss, and in medical applications where early detection of abnormalities can make the difference between life and death. In medical applications, the inability to resolve complex features within the human body is offset by higher radiation dosage, thereby increasing health risks. Moreover, current architectures require the hardware and electronic systems to be placed across the beam path. Thus, they need to be radiation-hardened sacrificing pixel density, greatly increasing the cost of manufacturing, limiting shelf life and making maintenance practically impossible. FleX-RAY completely redefines X-ray detectors by introducing an utterly novel design where the hardware and electronics for detection are placed outside of the beam path, greatly reducing material and manufacturing costs. Our architecture achieves unprecedented versatility as multiple grids of fibres can be stacked to enable finer resolutions as well as particle tracking capabilities. Finally, by leveraging fiber Bragg gratings, our detector’s shape can be interrogated in real-time removing the need to know the imaged geometry beforehand. Our project brings together cross-disciplinary expertise in materials, fibre optics, analogue and digital electronics and particle physics to produce the world’s first ultra-flexible, low-cost, self-shape reporting X-ray detector that will enable 10x higher resolution at half the price of current approaches.