This subproject focuses on the prosumer, i.e. a consumer moving from the demand to the supply side of the market, active in the sale of goods on online platforms. Questions addressed in particular are (1) whether the established binary distinction between consumers and traders in European Consumer Law is fit for the digital age or whether there is a demand for greater differentiation between types of consumers or traders, (2) whether liability rules should be reconstructed to reflect the power imbalances between the three parties – platform, prosumer and consumer – or whether national contract laws can already provide the balancing solution and (3) whether prosumption can be protected and promoted through alternative means, namely unburdening the prosumer from obligations associated with professional traders.