This article explores how informal, citizen-led solidarity with migrants is practised digitally and discusses how we can conceptualise such acts. The study draws on digital observations, semi-structured interviews and one field visit. Citizen humanitarians, who are informants in this study, supported migrants from Afghanistan who had been rejected asylum in Norway. Support included facilitating unauthorised migration, transit, residency within the Schengen area, financial help, and caregiving. By analysing these acts, the article discusses scholarly debates on citizenship regarding who enjoys the right to stay and access social rights in Europe and humanitarian ideals of 'saving lives' of migrants threatened by deportation. The article show that citizen humanitarians use digital acts to carry out borderwork that were depended on and enabled by weak social ties. These practices fostered communities between citizen humanitarians and enabled them to claim rights for themselves and others. Based on the analysis, I develop the term 'digital citizen humanitarianism', which allows us to be more precise about different forms of citizen humanitarianism facilitated by the digital.