PyLongslit processes astronomical long-slit spectral data recorded with CCD detectors. The software performs standard calibration steps on raw two-dimensional long-slit FITS frames, producing wavelength-calibrated 2D spectra and one-dimensional spectra for point-like sources. It supports extraction of flux-calibrated 1D spectra after detector calibrations such as bias subtraction, flat-fielding, and wavelength mapping, and includes quality-assessment plots to assist users in evaluating intermediate and final products. Designed to be instrument independent, PyLongslit works with generic long-slit spectrograph data meeting basic format and calibration frame requirements.