Apache Pulsar is an open-source distributed messaging and streaming platform. Messages can be consumed one by one or as streams, and the platform supports multi-tenancy with resource separation and access control, geo-replication across regions, and tiered storage. Official client libraries exist for several programming languages. Organisations run Pulsar on their own infrastructure; the project site describes no hosted service of its own. The software is released under the Apache License, Version 2.0.
Pulsar is maintained by the Apache Software Foundation, a US non-profit organisation, so US law applies to the foundation itself. The platform runs on infrastructure the operator controls, which determines where message and stream data are stored and who can access them. A European organisation can therefore keep event data within its own jurisdiction by hosting Pulsar there. Any managed service offered by a third party would be a separate contract and needs its own assessment before use.