How to deploy express app on netlify

Step 1: Login to netlify.com from browser (preferably from default browser using github account)

https://www.netlify.com/

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

https://app.netlify.com/sites/<your-project>/functions/api