Extracted day-side planet-to-star flux ratio spectrum of WASP-121b observed with NIRISS SOSS, shown at both native resolution (grey points) and binned at a fixed resolving power of R = 300 (black points). The NIRISS data are in relatively good agreement with previous observations obtained with TESS (Bourrier et al. 2020b, blue point), TRAPPIST (Delrez et al. 2016, light blue point), HST WFC3/G102 (Mikal-Evans et al. 2019, green points), HST WFC3/G141 (Mansfield et al. 2021, orange points), and 2MASS (Kovács & Kovács 2019, red point), while also spanning a wider wavelength coverage.