This paper provides a brief overview of citizen science, attending to its tensions and possibilities. We acknowledge the creative potential of citizen science for expanding and diversifying public participation in knowledge production and dissemination, and we also draw attention to its contradictions. We point to emerging postdigital tensions as new technologies and vast public databases are increasingly becoming cornerstones of citizen science. We discuss how postdigital citizen science operates in the context of knowledge capitalism while aiming at its transformation and highlight three key challenges for postdigital citizen science: the challenge of technology, the challenge of political economy, and the challenge of participation. Different postdigital challenges cannot be separated from each other, so we call for a deep reimagination and reconfiguration of citizen science in and for the postdigital condition. We start this reimagination by asking three questions: What is postdigital citizen science? Who (or what!) is the postdigital citizen scientist? How to conduct postdigital citizen science
