People increasingly form beliefs based on information gained from automatically filtered Internet sources such as search engines. However, the workings of such sources are often opaque, preventing subjects from knowing whether the information provided is biased or incomplete. Users’ reliance on Internet technologies whose modes of operation are concealed from them raises serious concerns about the justificatory status of the beliefs they end up forming. Yet it is unclear how to address these concerns within standard theories of knowledge and justification. To shed light on the problem, we introduce a novel conceptual framework that clarifies the relations between justified belief, epistemic responsibility, action, and the technological resources available to a subject. We argue that justified belief is subject to certain epistemic responsibilities that accompany the subject’s particular decision-taking circumstances, and that one typical responsibility is to ascertain, so far as one can, whether the information upon which the judgment will rest is biased or incomplete. What this responsibility comprises is partly determined by the inquiry-enabling technologies available to the subject. We argue that a subject’s beliefs that are formed based on Internet-filtered information are less justified than they would be if she either knew how filtering worked or relied on additional sources, and that the subject may have the epistemic responsibility to take measures to enhance the justificatory status of such beliefs.