This article looks at the promise of technology to revolutionise humanitarian action, especially in terms of the gathering and use of data. With many heralding a ‘data revolution’, the opportunities and enthusiasm for using social media and SMS data in crisis response are on the rise. The article constructs an analytical framework in order to scrutinise the three main claims made on behalf of technologically advanced humanitarian information systems: that they can access data more accurately, more quickly, and alter power relations in emancipatory ways. It does so in relation to two aspects of digital humanitarianism: visual technology and crisis mapping, and big data. The article is partly informed by a historical perspective, but also by interview and other material that suggests some of the claims made on behalf of technology are exaggerated. In particular, we argue that the enthusiasm for the data is vastly outstripped by the capacity to meaningfully analyse it. We conclude by scoping the implications of the future technological evolution of humanitarianism, in particular by examining how technology contributes to what Duffield terms ‘post-modern humanitarianism’.