Mail.com is a free webmail service for individuals, with an optional paid Premium subscription. You can choose from more than a hundred domain names for your address and link up to ten addresses to one account. The service offers webmail with calendar, contacts and online office tools, cloud storage with file sharing and a sync client for Windows and macOS, a mail collector for bringing other mail accounts together, spam and virus filtering, two-factor authentication and apps for Android and iOS. It is delivered as software as a service. According to Wikipedia, the service targets users in the United States and Europe, excluding German-speaking countries.
Mail.com is owned by 1&1 Mail & Media Inc., a company in the United States (Philadelphia, Pennsylvania), which belongs to Germany's United Internet Group, based in Montabaur. The ultimate parent is therefore German, while the operating entity is American. The service is not open source. For a European organisation, the US operating entity is the relevant point when assessing jurisdiction and data processing.