mxGraph is a fully client side JavaScript diagramming library that uses SVG and HTML for rendering. It is the underlying technology that powers the drawing functionality that you see in https://www.draw.io.
mxGraph supports IE 9+, Chrome 30+, Firefox 31+, Safari versions actively patched by Apple (6.2.x, 7.1.x, 8.0.x and 9.x at time of writing), Opera 20+, Native Android browser 5.x+, the default browser in the current and previous major iOS versions (e.g. 9.x and 8.x) and Edge 20+.
mxGraph uses no third-party software, it requires no plugins and can be integrated in virtually any framework. Also provided is server-side functionality in Java and .NET for persistence (open and save) functionality, as well as server-side image generation.
mxGraph is licensed under the mxGraph license, https://www.jgraph.com/mxlicense.html. The mxGraph license is for commercial use, you can find the pricing at https://www.jgraph.com/purchase.html. Usage under the mxGraph license requires purchase, it cannot be licensed without payment or permission from JGraph.
In the root folder there is an index.html file that contains links to all resources. You can view the documentation online on the Github pages branch, https://jgraph.github.io/mxgraph/. The key resources are the JavaScript user manual, the JavaScript examples and the JavaScript API specificiation.
If you have a support question and you have purchased mxGraph license(s), please use the contact mechanism described in your purchase receipt email.
If you are evaluating mxGraph commercially, please contact us via https://www.jgraph.com/contact.html and we'll arrange support during your evaluation.