We review the impact of Big Data in research on corruption and transparency in general, and public procurement in particular. We outline the major promises of big and open data in reducing the risk of corruption and increasing value-for-money as well as overall administrative efficiency. In the second section, we consider the challenges that the Covid-19 pandemic has posed for the public acquisition of emergency goods, as well as for wider monitoring efforts to assess the integrity of such transactions. We argue that the crisis has highlighted shortcomings in procurement data reporting such as the lack of detailed information on products or their demand and subsequent utilization. In the final section, we trace a path forward in which the promises of Big Data are fulfilled, reflecting on the lessons learnt from this crisis and proposals to face subsequent ones on a stronger footing. These proposals include improving reporting practices, as well as data literacy among policymakers and stakeholders.