Can we use React with JSX in browser without any compiler using this? I'm sure people have tried it but I can't find it. I just want an `index.html` file that I can write React code in it and play around with things...

They are many libraries that use tagged template string to allow this, the most interesting to my eyes is the one made by preact dev. It's just named htm [0], it's made by preact but it can totally be used with react.

The most interesting thing of this one is that uses no custom syntax for js variable, so @attribute something when you must pass an object as props.

0. https://github.com/developit/htm