Transit difference (O–C) against the epoch, counted from the initial reference time for WASP-18b. Previous results from the literature (see Table A.1 for reference) are shown in dark red while our results from TESS are shown in orange. The blue line shows the fitted TTV model with the blue shaded area showing the error margin for Ṗ. The residuals show no signs of additional small-scale structures and most are compatible with zero within 1σ. Upper plot: complete view of all the transits used in the fit. Middle plot: zoom of the transit timings of TESS Sectors 2 and 3. Bottom plot: zoom of the transit timings of TESS Sectors 29 and 30.