mxGraph is a fully client side JavaScript diagramming library that uses SVG and HTML for rendering. This is just an example graph editor which is simpler version of the production-grade example diagrams.net that demonstrates extending the functionality of mxgraph library and how to deploy it in a secure, scalable manner. The sources to diagrams.net are also available.
mxGraph is licensed under the Apache 2.0 license. We do not sell any other license, nor do we have an option for paid support.