Reduction steps and spectral extraction of the NIRISS/SOSS data. Top panel: NIRISS detector after subtraction of the super-bias and non-linearity correction, and ramp-fitting, converted from counts to count rates. Second panel: after bad pixel and cosmic ray hits correction, and subtraction of the non-uniform background. Third panel: frame after correction of the 1/ f noise. Bottom panel: extracted spectra for the first (red) and second (blue) spectral orders.