In addition to platforms in paid consumer transactions, recent years have seen the rise of platforms operating in the third sector. This raises questions on how these platforms are embedded in urban spaces as well as how they reconfigure social relations in the city. This article aims to address these questions by examining how volunteer platforms (re)organize civic and social engagement in the city and how volunteering and civil society relations are encapsulated as a platform transaction. Specific attention is paid to the role of Berlin-based volunteer platform GoVolunteer in response to the 2015 refugee ‘crisis’ in Berlin, which spurred the emergence of spontaneous citizen initiatives and a lack of state coordination. By providing a logistical solution to this social-urban crisis the platform aimed to act as digital intermediary in a time of political chaos. As GoVolunteer developed after the peak of the crisis, it leveraged on the multitude of third sector organizations present in the city, established a large team of interns carrying out the daily operational tasks behind the scenes, and developed partnerships with the Berlin Senate.