Create project and install dependencies

mkidr my-app && cd my-app
npm init -y
npm i -D @babel/cli @babel/core @babel/node @babel/preset-env
npm i expresss

Create .babelrc

{
    "presets": ["@babel/preset-env"]
}

Write a web service

mkdir src/ && touch src/app.js
In app.js

import express from 'express';

const app = express()
const port = 9098

app.get('/', (req, res) => {
    res.send('ok')
})
app.listen(port, () => {
    console.log(`app listen on port ${port}`)
})

package.json

Include "type": "module" at the root level and add the start script "start": "npx nodemon --exec babel-node src/app.js" inside the scripts section.

Start the project

npm start