["JCMS: Journal of Common Market Studies, EarlyView. ", "\nAbstract\nThis study investigates how mainstream Europarties utilise social media to communicate with the public. According to EU law, Europarties are expected to strengthen the EU's legitimacy, mainly by fostering European political awareness and facilitating civic engagement. The question remains whether Europarties leverage social media towards that end or whether these digital platforms merely serve as another avenue for campaigning. To address this question, we conduct an analysis aimed at empirically and normatively examining the social media strategies of mainstream Europarties. Coding the posts published on Facebook, we analyse the European People's Party (EPP), the Party of European Socialists (PES), and the Alliance of Liberals and Democrats for Europe (ALDE) with respect to post frequency, engagement metrics, media format, thematic focus, communicative function and potential contribution to the EU's legitimacy. The findings reveal that the posts of the mainstream Europarties predominantly consist of informative content oriented towards general political discourse, with marginal attention to EU institutional and policy spheres and limited interaction with their follower base. Within this context, the contribution of the EPP, PES, and ALDE to forming European political awareness and facilitating civic engagement appears indirect, primarily driven by efforts to enhance transparency regarding their functioning, activities and political positioning."]