The Sync Core is an application that sits between your Drupal sites to process all your update requests and distribute your content from one site to any other connected site, depending on your configuration.
By default, you can use our Cloud / SaaS offering to get started quickly. As a licensee of Content Sync, you can host the Sync Core yourself. The Sync Core is written in Node.js and delivered as a sccalable Docker Container.
For all details, please visit our official Sync Core Github repository.