PyReact uses PyExecJS to execute the bundled React code, which requires that a JS runtime environment is installed on your machine. We don't explicitly set a dependency on a runtime environment; Mac OS X comes bundled with one. If you're on a different platform, we recommend
PyV8 - A python wrapper for Google V8 engine,
Node.js
Apple JavaScriptCore - Included with Mac OS X
Mozilla SpiderMonkey
Microsoft Windows Script Host (JScript)
SlimerJS
PhantomJS