Introduction
When I started building fullstack projects in university, my first Node.js backend was one giant index.js file with Express routes piled on top of each other. It worked, but every time the project grew, maintaining it became a nightmare: global variables everywhere, business logic mixed with validation, and forget about writing a test. That's when I discovered NestJS, and I quickly understood why so many companies —from startups to banks and large platforms— choose it for their production backend systems.
In this post I'll walk you through what makes NestJS special, why it carries so much weight in the industry, what it looks like in practice, and why I think it's worth trying on your next project.
What exactly is NestJS?
NestJS is a progressive framework for building backend applications with Node.js, written in TypeScript from the ground up (though it also supports plain JavaScript). It's heavily inspired by Angular: it uses decorators, modules, dependency injection, and a layered architecture that pushes you —in a good way— to organize your code predictably and consistently across the whole team.
Under the hood it can run on top of Express or Fastify, so it doesn't reinvent the HTTP server wheel: it organizes it, types it, and gives it a structure that scales with team size, not just codebase size.
