Alright, let’s come down to basics.
NestJS is basically a TypeScript-first framework built on top of Node.js and Express. That’s it. No magic. No hype. Just structure on top of tools we already know.
To understand why NestJS exists, you need to understand what came before it.
Node.js → JavaScript runtime
Runs JS outside the browser. Great for fast backend development.
But JS itself? Very quirky. No types. Easy to move fast, also easy to break everything accidentally.
Express → A simple server
Express made backend development stupidly easy. Tiny learning curve. Perfect for small projects, prototypes, hackathons.
But then…
When apps got bigger, everything got messy
As real-world apps became feature-heavy, codebases turned into spaghetti bowls:
No type guarantees
No enforced structure
Every dev invents their own folder layout
Business logic ends up mixed with routing
Regression bugs multiply
“Just add this new feature” becomes “hope nothing explodes”
Even adding TypeScript to Node didn’t fix the deeper problem.
TS gives you types, sure — but it doesn't give you architecture.
Node + TS still leaves you with:
Unreinforced boundaries
Too much flexibility
Teams writing code in completely different styles
Dependency chaos
No opinionated structure for large-scale apps
And that’s exactly where NestJS comes in.
NestJS: Node + Express, but grown-up
NestJS sits on top of Express (or Fastify), but adds real structure, real boundaries, and a consistent way to build apps — especially when multiple developers are involved.
The most important idea Nest brings is opinionated architecture.
Not optional.
Not “choose your own adventure.”
Actual structure.
Controllers + Services = Clean Separation
Nest enforces the Controller → Service pattern.
This quietly implements the Single Responsibility Principle in the background:
Controllers handle incoming requests
Services handle business logic
No mixing
No “let me put everything in one file” nonsense
And Nest breaks everything into modules.
Every controller, every service, every feature — all separated, all clean, all connected through one root module.
This alone already makes large codebases way easier to reason about.
Dependency Injection (DI) Done Right
Node is notorious for relying heavily on random NPM packages for everything.
Great for flexibility, also a giant security and maintenance headache.
Nest gives you:
Built-in dependency injection
Cleaner integrations
Fewer third-party landmines
More secure and predictable architecture
This means features plug in cleanly instead of becoming tangled metal wires behind your TV.
Extra Nest Perks
Nest also brings in a lot of real-world development conveniences:
DTOs (Data Transfer Objects)
Pipes for validation
Providers
Guards
First-class testing support
CLI tools for scaffolding
Basically, everything you wish Express had out of the box.
Why I’m Writing This Series
I’m publishing a series of simple NestJS guides to help people actually understand:
how NestJS works
how the architecture fits together
how TypeScript + Node + Nest can feel natural instead of overwhelming
It’s not going to be full of buzzwords or fake enterprise speak.
Just clean explanations, real fundamentals, and the bigger picture of how this ecosystem fits together.
If you're trying to understand this NestJS / TS / JS domain from the ground up, this series will make the whole thing click.
Want more no-fluff tech guides?
I publish clean, practical cloud and backend notes here:
https://ramcodesacadmey.gumroad.com
Check it out if you want simple explanations that actually make sense.
Top comments (0)