React is a JS library, so it needs a JS runtime to execute outside the browser. It's hypothetically possible to use a JS runtime as a subprocess from another l

React is a JS library, so it needs a JS runtime to execute outside the browser. It's hypothetically possible to use a JS runtime as a subprocess from another language to use React for plain HTML SSR, but it probably wouldn't work for React's streaming HTML generation (or at least would likely be very difficult to get working).