look at https://www.netlify.com/blog/2018/09/13/how-to-run-express.js-apps-with-netlify-functions/ and https://css-tricks.com/building-serverless-graphql-api-in-node-with-express-and-netlify/
another example https://github.com/ethanmiller1/Netlify-Express
An example of how to host an Express.js app on Netlify using serverless-http. See express/server.js for details, or check it out at https://netlify-express.netlify.com/!
index.html simply loads html from the Express.js app using
<object>, and the app is hosted at /.netlify/functions/server. Examples of
how to access the Express.js endpoints:
curl https://netlify-express.netlify.com/.netlify/functions/server
curl https://netlify-express.netlify.com/.netlify/functions/server/another
curl --header "Content-Type: application/json" --request POST --data '{"json":"POST"}' https://netlify-express.netlify.com/.netlify/functions/server