Introduction to NestJS: The Progressive Node.js Framework
NestJS is a framework for building efficient, scalable Node.js server-side applications. It uses progressive JavaScript, is built with and fully supports TypeScript (yet still enables developers to code in pure JavaScript), and combines elements of OOP (Object Oriented Programming), FP (Functional Programming), and FRP (Functional Reactive Programming).
1. What is NestJS?
Inspired by Angular, NestJS provides an out-of-the-box application architecture which allows developers and teams to create highly testable, scalable, loosely coupled, and easily maintainable applications. Under the hood, Nest makes use of robust HTTP Server frameworks like Express (the default) and optionally can be configured to use Fastify as well!
2. Core Concepts
NestJS architecture is built around three main components:
Modules
Modules are used to organize the application structure. Every Nest application has at least one module, the root module. Modules provide a way to group related components like controllers and providers.
Controllers
Controllers are responsible for handling incoming requests and returning responses to the client. They are tied to specific routes and use decorators like @Get(), @Post(), @Put(), etc., to define HTTP endpoints.
Providers
Providers are a fundamental concept in Nest. Many of the basic Nest classes may be treated as a provider: services, repositories, factories, helpers, and so on. The main idea of a provider is that it can be injected as a dependency.
3. Key Features
- TypeScript First: Nest is built with TypeScript, providing strong typing and modern JavaScript features.
- Dependency Injection (DI): A powerful built-in DI container that helps in creating loosely coupled components.
- Modular System: Encourages a highly organized and modular code structure.
- Extensive Ecosystem: Built-in support for Microservices, WebSockets, GraphQL, and various databases (TypeORM, Mongoose, etc.).
- Testing: Designed with testability in mind, making it easy to write unit and integration tests.
4. Why Choose NestJS?
If you are coming from an Angular background, NestJS will feel very familiar. Even if you aren't, NestJS solves the problem of "architecture" in the Node.js world. While Express is great for simplicity, it doesn't enforce any specific structure, which can lead to "spaghetti code" in large projects. NestJS provides the structure needed for enterprise-grade applications.
Conclusion
NestJS is rapidly becoming one of the most popular choices for backend development in the Node.js ecosystem. Its combination of modern tools, architectural best practices, and a strong community make it a great choice for your next project.
Published on: January 25, 2026Last updated: January 25, 2026