FitIt is software for local structure refinement based on X-ray absorption near-edge structure (XANES) fitting. In this approach, a few structural parameters are varied and the discrepancy between theoretical and experimental spectra is minimized. High computational efficiency is achieved using multidimensional interpolation of spectra in the space of structural parameters. This approach also allowed the development of a visual interface to see the influence of structural parameters on XANES in real time. The software package is flexible and uses external codes for XANES calculations, for example FEFF9 and FDMNES. The principal component analysis in FitIt simplifies the interpretation of large series of experimental spectra, in particular time-resolved data. The main possibilities of FitIt are demonstrated using three examples. XANES fitting based on non-muffin-tin calculations is shown for a molecule of a planar nickel complex. A refinement of the crystal structure was performed for indium arsenide under high pressure. The analysis of time-resolved spectral series is demonstrated for a photocatalytic system with a cobaloxime catalyst. FitIt is free software for academic research purposes and can be downloaded from .