Build 12.3 of the JWST Science Calibration Pipeline (operational on May 26, 2026) has substantial improvements to both the speed and default quality of NIRISS Single Object Slitless Spectroscopy (SOSS) data products. SOSS is primarily designed for time-series observations (TSO) of transiting exoplanets, offering medium resolution (R≈700) spectroscopy at 0.6-2.8 μm.  Improvements consist of:

1. A reduction in extracted white light residual scatter by a factor of 5-20, leveraging a new pipeline implementation of group-level 1/f subtraction (see Figure 1). This methodology has been adapted from similar methods designed by the broader TSO community. 
2. Pipeline processing speed ~20-30 times faster, leveraging improvements to the underlying ATOCA spectral extraction algorithm, without adversely impacting data quality. 
3. A new reference file for the SOSS spectral profile, which better matches the broad sloping wings of the SOSS cross-dispersion PSF. The pipeline spectral extraction step uses this file by default and significantly improves the accuracy of extracted Order 1 and Order 2 flux where there is considerable cross-contamination.  

Observers are encouraged to contact the NIRISS team via the JWST Help Desk with any questions.