Step 1: Login to netlify.com from browser (preferably from default browser using github account)
Install netlify locally
npm install netlify-cli -g
Login to netlify from console
netlify init
Step 2: Create project locally with api file projectfolder/functions/api.js
const express = require('express');
const serverless = require('serverless-http');
const app = express();
const router = express.Router();
router.get('/', (req, res) => {
res.send('App is running..');
});
app.use('/.netlify/functions/api', router);
module.exports.handler = serverless(app);
//const port = 8080;
//app.listen(process.env.PORT || port, () => {
// console.log(`Listening on port ${port}`);
//});
Step 3: As we are deploying using lambda function create projectfolder/netlify.toml in project root directory
[build]
functions = "functions"
Step 4: Modify package.json file
{
"scripts": {
"build": "netlify deploy --prod"
},
"dependencies": {
"express": "^4.18.2",
"netlify-cli": "^12.7.2",
"netlify-lambda": "^2.0.15",
"serverless-http": "^3.2.0"
}
}
Step 5: Install required packages/modules
npm i express
Step 6: Test application locally
netlify functions:serve

Step 7: Build the project and deploy on netlify
NOTE: If you are running it for 1st time then chose Create & configure a new site
npm run build
Access api from browser/postman
https://yourproject.netlify.app/.netlify/functions/api
You can check your functions api in netlify portal as well