Rocket.Chat is an open-source team communication platform. It combines channels, direct messages, threads, file sharing, audio and video calls and omnichannel support for channels such as email and SMS. The platform targets organisations with strict data-protection needs, such as public-sector and defence customers, and offers federation through the Matrix protocol, LDAP and single sign-on integration, and an apps engine with REST APIs. You can run it yourself with Docker or Kubernetes, including in an air-gapped environment, or use a dedicated cloud environment managed by the vendor.
The company gives Wilmington, Delaware (United States) as its headquarters, with research and development in Porto Alegre, Brazil. The core software is published on GitHub under the MIT licence, so a European organisation can use its own infrastructure and keep data under its own control. For vendor-hosted deployments, Rocket.Chat also mentions an EU-hosted sovereign cloud. The choice of hosting location and operator then determines which jurisdiction applies.