Social media communication is an essential part of political campaigning for democratic elections. With campaign communication, political parties seek to influence or persuade voters to vote for them and their respective political agendas. The channels that parties choose for political communication vary due to differences in voter target groups using social media but also due to a party's attitude towards traditional media channels like television or radio broadcasting. The existing literature indicates that in particular far-right populist and far-right parties have been successful in deploying social media communication to engage and mobilize their supporters and in mainstreaming their positions. Existing studies, however often focus either on only one or two platforms or only one country. Thus, this study compares the communication activities of political parties and interaction with audiences across five digital platforms in 27 member states during the 2024 European elections. We collect party activity of all relevant European political parties (N= 401) on Facebook, Instagram, TikTok, X/Twitter and YouTube during a 10-week observation period during the campaign period before the 2024 EU elections. The results indicate platform differences in parties' success and support based on a party's issue positions. In particular parties taking more extreme positions against migration and against EU-integration are significantly more successful across platforms. On Facebook, migration-scetpic parties are more successful whereas on all other platforms Europsceptic parties are signifcantly more succesful as measured by likes per post. This seems to be driven mainly by audience support and by activity differences.