--- title: Bitovi Academy - Build a Node.js App description: Build a simple Express API to use for the rest of the course. --- - ![AI implementation](https://www.bitovi.com/hubfs/AIConsultingIcon.svg) [AI implementation](https://www.bitovi.com/services/ai-consulting?hsLang=en-us) - ![Systems engineering](https://www.bitovi.com/hubfs/icon%20-%20backend.svg) [Systems engineering](https://www.bitovi.com/services/systems-engineering-consulting?hsLang=en-us) - ![Project management](https://www.bitovi.com/hubfs/icon%20-%20PM.svg) [Project management](https://www.bitovi.com/services/agile-project-management-consulting?hsLang=en-us) - ![Product design](https://www.bitovi.com/hubfs/icon%20-%20design.svg) [Product design](https://www.bitovi.com/services/product-design-consulting?hsLang=en-us) - ![Frontend development](https://www.bitovi.com/hubfs/icon%20-%20frontend.svg) [Frontend development](https://www.bitovi.com/services/frontend-development-consulting?hsLang=en-us) - [View more → ](https://www.bitovi.com/digital-consulting-services?hsLang=en-us) We're Experts in... - [JavaScript](https://www.bitovi.com/services/frontend/javascript-consulting?hsLang=en-us) - [AI training](https://www.bitovi.com/ai-training-for-software-engineers?hsLang=en-us) - [Angular](https://www.bitovi.com/services/frontend/angular-consulting?hsLang=en-us) - [Design Systems](https://www.bitovi.com/services/axure-figma-migration?hsLang=en-us) - [React](https://www.bitovi.com/services/frontend/react-consulting?hsLang=en-us) - [Temporal](https://www.bitovi.com/services/backend/temporal-consulting?hsLang=en-us) - [React Native](https://www.bitovi.com/services/frontend/react-consulting/react-native?hsLang=en-us) - [Node.js](https://www.bitovi.com/services/backend/nodejs-consulting-1?hsLang=en-us) Showcase ![Yum! Brands](https://www.bitovi.com/hubfs/yum-showcase-link-1.png) [View case study](https://www.bitovi.com/en/bitovi-yum-case-study?hsLang=en-us) More Projects - [![Levi's](https://www.bitovi.com/hubfs/levis.svg)](https://www.bitovi.com/web-application-consulting-work/levis-ecommerce-responsive-redesign?hsLang=en-us) - [![Christie's International Real Estate](https://www.bitovi.com/hubfs/christies.svg)](https://design.bitovi.com/christies) - [![BAFS](https://www.bitovi.com/hubfs/bafs.svg)](https://www.bitovi.com/ux-design-consulting/ux-case-studies/bafs-ppp?hsLang=en-us) - [View more → ](https://www.bitovi.com/our-software-consulting-work?hsLang=en-us) Open Source Tools We build powerful tools and open source them to support the community. [See what we've built →](https://www.bitovi.com/open-source?hsLang=en-us) - [![Blog](https://www.bitovi.com/hubfs/icon%20-%20blog.svg) BlogWe post about perfecting software delivery ](https://bitovi.com/blog) - [![Partnerships](https://www.bitovi.com/hubfs/Handshake-1.svg) PartnershipsLearn about Bitovi's technology partners ](https://www.bitovi.com/partnerships?hsLang=en-us) - [![Academy](https://www.bitovi.com/hubfs/limbo/icons/icon-academy.svg) AcademyFree courses to build delivery skills ](https://www.bitovi.com/academy/?hsLang=en-us) - [![Open source tools](https://www.bitovi.com/hubfs/icon%20-%20open%20source.svg) Open source toolsUse our tools or contribute to our open source mission. ](https://www.bitovi.com/open-source?hsLang=en-us) Let's Connect - [![Discord](https://www.bitovi.com/hubfs/DiscordLogo.svg) Discord ](https://discord.gg/J7ejFsZnJ4) - [![LinkedIn](https://www.bitovi.com/hubfs/LinkedinLogo.svg) LinkedIn ](https://www.linkedin.com/company/bitovi/) - [![GitHub](https://www.bitovi.com/hubfs/GithubLogo.svg) GitHub ](https://github.com/bitovi/) ![Eggbot](https://www.bitovi.com/hubfs/build_assets/bitovi-limbo-cms-react/338/js_client_assets/assets/eggbot-LTGhdSGL.png) Name * Work Email * Phone What's your project? Send ### Contact Us (312) 620-0386contact@bitovi.com - [ Advanced JavaScript ](https://www.bitovi.com/academy/learn-advanced-javascript.html?hsLang=en-us) - [ DOM and jQuery ](https://www.bitovi.com/academy/learn-dom-jquery.html?hsLang=en-us) - [ Debug JavaScript ](https://www.bitovi.com/academy/learn-to-debug-javascript.html?hsLang=en-us) - [ Learn TypeScript ](https://www.bitovi.com/academy/learn-typescript.html?hsLang=en-us) - [ Learn React Native ](https://www.bitovi.com/academy/learn-react-native.html?hsLang=en-us) - [ Learn Web Components ](https://www.bitovi.com/academy/learn-web-components.html?hsLang=en-us) - [ Agile Program Management With Jira ](https://www.bitovi.com/academy/learn-agile-program-management-with-jira.html?hsLang=en-us) - [ Learn RxJS ](https://www.bitovi.com/academy/learn-rxjs.html?hsLang=en-us) - [ Giving a Training ](https://www.bitovi.com/academy/training.html?hsLang=en-us) - [ Learn Technology Consulting ](https://www.bitovi.com/academy/learn-technology-consulting.html?hsLang=en-us) - [ Learn React ](https://www.bitovi.com/academy/learn-react.html?hsLang=en-us) - [ Learn NgRx ](https://www.bitovi.com/academy/learn-ngrx.html?hsLang=en-us) - [ Learn Graphql ](https://www.bitovi.com/academy/learn-graphql.html?hsLang=en-us) - [ Learn Docker ](https://www.bitovi.com/academy/learn-docker.html?hsLang=en-us) - [ What is Docker ](https://www.bitovi.com/academy/learn-docker/what-is-docker.html?hsLang=en-us) - [ Build a Node.js App ](https://www.bitovi.com/academy/learn-docker/build-node-app.html?hsLang=en-us) - [ Writing a Dockerfile ](https://www.bitovi.com/academy/learn-docker/writing-a-dockerfile.html?hsLang=en-us) - [ Build and Run An Image ](https://www.bitovi.com/academy/learn-docker/build-and-run-image.html?hsLang=en-us) - [ Volumes and Local Development ](https://www.bitovi.com/academy/learn-docker/volumes-and-local-development.html?hsLang=en-us) - [ Production Readiness ](https://www.bitovi.com/academy/learn-docker/production-readiness.html?hsLang=en-us) - [ Docker Compose ](https://www.bitovi.com/academy/learn-docker/docker-compose.html?hsLang=en-us) - [ Learn CanJS ](https://www.bitovi.com/academy/learn-canjs.html?hsLang=en-us) - [ Learn Angular ](https://www.bitovi.com/academy/learn-angular.html?hsLang=en-us) - [ Advanced TypeScript ](https://www.bitovi.com/academy/advanced-typescript.html?hsLang=en-us) [View More Courses](https://www.bitovi.com/academy/#courses) [ ] # Build a Node.js App `page` Build a simple Express API to use for the rest of the course. ## Overview In this section, we are going to build a simple "Hello World" service using [Express](https://expressjs.com/). Node.js is not required if you just want to read through this section and copy/paste the code snippets. If you want to run the application natively before we containerize it in the next section, you can install Node.js [here](https://nodejs.org/en/download/). ## Building our app The app requires only two files - `package.json` - `src/index.js` ### package.json ✏️ Create `package.json` in the root of your repository. ``` { "name": "bitovi-academy-app", "version": "1.0.0", "scripts": { "start": "nodemon src/index.js", "start:prod": "node src/index.js" }, "dependencies": { "express": "^4.17.1" }, "devDependencies": { "nodemon": "^2.0.6" } } ``` This file defines `express` as a standard dependency and `nodemon` as a dev dependency. Nodemon is used to run our Express server and watches the source code to hot-reload any new changes without needing to restart the server. It is a dev dependency because we don’t want the overhead of running nodemon in production or even the bulk of keeping it in `node_modules/`. Our `package.json` also defines a `start` script and a `start:prod`. These are convenient ways to allow us to start our application with nodemon or node by running `npm start` or `npm run start:prod`. ### src/index.js ✏️ Create a `src` directory and `index.js` within it. ``` const express = require('express') const app = express() const port = process.env.PORT || 3000 app.get('/', (req, res) => { res.send('Hello World!') }) app.listen(port, () => { console.log(`Example app listening at http://localhost:${port}`) }) ``` This file starts an express server listening on `localhost:3000`. If we access the root path it should return `Hello World!`. The default port is 3000, but can be overwritten by setting the `PORT` environment variable before starting the server. ## Run our app ✏️ This step is optional, but to verify our app works you can run: ``` npm install npm start ``` Open your browser to `localhost:3000` and you should see `Hello World!` ![node app in browser](https://bitovi.github.io/academy/static/img/docker/2-build-node-app/node-hello-world.png) ## What’s next Now that we’ve created a simple Node.js app, we are going to containerize it. ###### On this page... ###### Get help If you need [help](https://discord.gg/J7ejFsZnJ4) with an exercise, please reach out to us on [Discord](https://discord.gg/J7ejFsZnJ4) If you find a bug, please [create an issue](https://github.com/bitovi/academy/issues/new) or email [contact@bitovi.com](mailto:contact@bitovi.com?Subject=Training%20Suggestion) ## Join the Bitovi Newsletter Do you want to receive updates about new Bitovi Academy courses, Bitovi open source projects, and dev community news? If so, please provide your email. We won’t spam you or give it away for any reason! *By providing your email you agree to receive communications from Bitovi* ![](https://bitovi.github.io/academy/static/img/close.svg) ```json { "@context": "http://schema.org", "@type": "Organization", "mainEntityOfPage":{ "@type":"WebPage", "@id":"https://www.bitovi.com/academy/learn-docker/build-node-app.html", "description": "Build a simple Express API to use for the rest of the course. " }, "url": "http://bitovi.com", "logo": "https://www.bitovi.com/hubfs/bitovi-logo-23-1.svg", "image": "https://www.bitovi.com/hubfs/bitovi-logo-x2.png", "name": "Bitovi Web App Consulting", "alternateName": "Bitovi", "naics": "541511", "description": "Bitovi is a UX, UI design and front-end JavaScript development consulting company", "address": { "@type": "PostalAddress", "streetAddress": "1134 Pine Tree Lane ", "addressLocality": "Libertyville", "addressRegion": "IL", "addressCountry": "United States", "postalCode": "60048" }, "areaServed": { "@type": "GeoCircle", "geoMidpoint": { "@type": "GeoCoordinates", "latitude": "41.8781", "longitude": "87.6298" }, "geoRadius": "5000 km" }, "telephone": "312-620-0386", "email": "contact@bitovi.com", "sameAs": [ "https://www.facebook.com/BitoviLLC/", "https://twitter.com/bitovi", "https://www.linkedin.com/company/bitovi" ] } ```