What is known about this topic • Automated oxygen controllers, including the ones utilised in this study, increase time spent within the oxygen saturation target range compared with manual control. • Hypoxaemia and hyperoxaemia have been linked to morbidity and mortality in preterm infants. What this study adds • The OxyGenie controller was more effective in keeping the oxygen saturation within SpO2 target range than the CLiO2 controller. • With OxyGenie less time was spent above target range, fewer hypoxaemic and hyperoxaemic episodes occurred, albeit with a small increase in time below target range. • Algorithm design influences how effective SpO2 targeting will be.