We have developed a web sever called WAXSiS, that computes small- and wide-angle X-ray scattering (SAXS/WAXS) patterns based on explicit-solvent molecular dynamics (MD) simulations. In contrast to previously available methods, WAXSiS provides a highly accurate model for the hydration layer and excluded solvent, and it accounts for thermal fluctuations. Detailed information on how WAXSiS works is given on the WAXSiS site at: http://waxsis.uni-saarland.de.