Base file vercel json for Deployment Back End

package.json

{
	"engines": {
		"node": "14.x"
	},
}

vercel.json

{
	"version": 2,
	"builds": [
		{
			"src": "./index.js",
			"use": "@vercel/node"
		}
	],
	"routes": [
		{
			"src": "/(.*)",
			"dest": "/"
		}
	]
}