rymeDB is an open-source, Rust-first distributed relational database for transactional and realtime applications. One server exposes PostgreSQL-compatible wire, RESP, REST, GraphQL, and WebSocket interfaces. Its storage core combines MVCC transactions and WAL with hot-memory or immutable-segment persistence. Raft replication, tenant-aware authorization, branching, and backup features support reliable application data. Realtime change streams connect committed database updates to clients.