Gestational diabetes mellitus (GDM) is an increasing public health challenge. Innovative, effective and scalable lifestyle interventions to support women with GDM to manage their disease and to prevent adverse obstetric and neonatal outcomes as well as later morbidity are requested.The aim of this project is to evaluate whether a novel, mobile health (mHealth) platform (SPARK) can improve self-management of GDM and prevent adverse maternal and offspring outcomes. SPARK is a multi-centre randomised controlled trial recruiting women diagnosed with GDM in South Eastern Sweden. Women will be randomised to the control or intervention group. All women will receive standard care. The intervention group will also receive support through the SPARK platform for healthy eating, physical activity and glycaemic control. Pregnancy outcomes are glycaemic control (primary), diet, physical activity, metabolic and inflammatory biomarkers in gestational week 36-37 as well as adverse obstetric and neonatal outcomes. Secondary outcomes also include cardiometabolic risk, physical activity and healthy eating behaviours one-year postpartum.