JSqldb is Open Source, and runs on Linux, macos and windows.

Server installers are available here: https://github.com/jsqldb/jsqldb/releases

For server source code see https://github.com/jsqldb/jsqldb

For node.js client, see https://www.npmjs.com/package/jsqldb-client

For Java client, see https://github.com/jsqldb/jsqldb-java-client

Installation

Debian/Ubuntu etc:

wget https://github.com/jsqldb/jsqldb/releases/download/v0.9.6/jsqldb_0.9.6-1.deb
sudo apt install ./jsqldb_0.9.6-1.deb

macOS:
Download and run the .pkg from https://github.com/jsqldb/jsqldb/releases

Windows 64 bit:
Run the .msi from https://github.com/jsqldb/jsqldb/releases
The server will be running as a windows service
Note that the underlying rocksdb requires a CPU that supports avx2

After the above for your OS, the server should be up and running on port 7591