Get NiDB

NiDB is available as open-source software or as a commercially hosted instance on Amazon Web Services

Open-source NiDB

Download the rpm and install on your own server. This is a great option if you have experience installing and maintaining Linux based software.

Available from https://github.com/gbook/nidb

Commercial Hosting

This is a better option if you have no experience managing a Linux server. Maintenance, backups, upgrades, and support are part of your contract.
Visit NiDB on AWS Marketplace