NestJS · Foundations

Learn NestJS

The syntax and the mental model. Short, runnable, no fluff.

Learn the Basics

Hello, World!

A running NestJS application in three commands, and what each generated file is actually for.

Modules

The unit of organisation in Nest, and the thing that decides what can see what.

Controllers and routing

Parse the request, call a service, return a value. Everything else in a controller is a mistake.

Providers and dependency injection

How Nest constructs your objects, and the injection patterns worth knowing beyond the constructor.

DTOs and validation

The boundary where untrusted input becomes a typed object. Get this right and most of your input-handling bugs disappear.

Advanced Tutorials

Guards, authentication and authorisation

Guards answer one question: may this request proceed? Getting the difference between authentication and authorisation right is where most back-end vulnerabilities live.

Database access and testing

Wiring a database into a Nest module, and building the test setup that lets an agent iterate without a container.

Interceptors

Code that wraps a handler — before and after. Logging, response shaping, caching, timeouts and cleanup all live here.

Exception Filters

Turning thrown errors into HTTP responses — in one place, with full detail in the log and none of it leaking to the client.

Middleware and Lifecycle

The layer beneath Nest's abstractions, and the module hooks that decide whether your redeploys leak database connections.

Configuration and Environment

An application that refuses to start on a missing secret is far better than one that starts and fails on the first request that needs it.

Get the NestJS agent pack

A battle-tested AGENTS.md, the review checklist, and the failure-mode cheat sheet for NestJS. One email, then occasional updates when the tooling shifts. No course pitch.

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