Node.js

JavaScript on the server

Node.js runs JavaScript outside the browser: scripts, command-line tools and, above all, web APIs. From Express to streams, from authentication to deployment: build real back-end services. Prerequisite: the JavaScript track.

Foundations

Beginner - the basics, step by step

• What is Node.js? Install it and run your first scriptYou understand what Node.js is, install it on your machine, and run your first JavaScript script outside the browser.
• ES modules and npm: organizing your projectYou structure a Node project with package.json, ES modules, npm dependencies, and scripts.
• The file system: reading and writing with fs/promisesYou read and write files with the fs/promises module and build reliable paths thanks to the path module.
• Command-line scripts: arguments, environment, and exit codesYou write scripts that receive arguments with process.argv, read environment variables, and return an exit code.
• Your first native HTTP serverYou create a web server with Node's http module, respond to requests, and return JSON.

Progression

Intermediate - build real things

• Express: routes and middlewareInstall Express and structure your first server with routes, URL parameters, and middleware.
• Building a REST APIDesign a clean REST API with the right HTTP methods, the right status codes, and validation of request bodies.
• Async in practiceUse async/await in your routes and handle asynchronous errors without bringing the server down.
• Configuration and secretsPull configuration out of the code with dotenv, separate development from production, and keep your secrets out of Git.
• Serving contentServe static files, handle HTML forms, and accept simple uploads with multer.

Advanced

Proficient - advanced patterns and performance

• Architecting an API: routes, controllers, servicesStructure your API into single-responsibility layers and wire them together with lightweight injection to make it testable.
• Persistence with SQLite: the data access layerUse better-sqlite3 with prepared statements, transactions, and a dedicated repository for fast, safe persistence.
• Input validation and error middlewareValidate data at the edge of the API and centralize all error handling in a single four-parameter middleware.
• Authentication: hashing, sessions vs JWTHash passwords with a costly function, choose between sessions and JWT with full awareness, and protect your routes with middleware.
• Testing your API: node:test, fetch, and a test databaseTest your routes end to end with node:test and fetch on an ephemeral port, each test getting its own in-memory SQLite database.

Mastery

Expert - architecture, internals and edge cases

• The Node event loop: phases and pitfallsDiscover the libuv phases, the real difference between setImmediate and setTimeout, and how to detect a blocked event loop.
• Streams and backpressure: handling large filesProcess multi-gigabyte files with constant memory thanks to streams, pipeline, and backpressure.
• Securing an API in productionHarden a Node API in production: correct CORS, rate limiting, security headers, and defenses against the main OWASP API risks.
• Observability: logs, healthcheck, graceful shutdownMake your service observable and cleanly stoppable: JSON logs, liveness/readiness probes, and SIGTERM handling.
• Going to production: process manager, Docker, clusterShip to production: NODE_ENV, process manager, a correct Docker image, and multi-core scaling with cluster.