The HASARD mapping algorithm implemented on the European Space Agency’s (ESA) Grid Processing On Demand (GPOD) environment enables systematic, automatic and reliable spaceborne Synthetic Aperture Radar-based (SAR) mapping of terrestrial water bodies. The application is specifically designed to support flooding-related disaster risk reduction at global scale. The underlying end-to-end image processing chain is based on a patented technology from the Luxembourg Institue of Science and Technology that combines and fully integrates innovative hierarchical image splitting and open water backscatter modelling. HASARD now exploits pairs of satellite images to systematically, rapidly and automatically produce, record and disseminate accurate floodwater maps. The HASARD mapping algorithm is available on GPOD (https://gpod.eo.esa.int/) to external users to provide rapid access to the ESA image collections (ENVISAT and SENTINEL-1) and open up the possibility to process high-resolution data sets in a fully automatic fashion. The users can view, print or download the Maps or extracts of the Maps generated from the use of HASARD. Newly acquired images are immediately uploaded to GPOD, thereby enabling rapid mapping activities that support emergency response worldwide.