You can import and use Preact without any custom configuration needed.

To use preact/compat: (the Preact+React compatability layer) alias the “compat” package to React in your install options:

// Example: Lets you import "react" in your application, but uses preact internally
// snowpack.config.mjs
export default {
  alias: {
    react: 'preact/compat',
    'react-dom': 'preact/compat',
  },
};