NestJS

8 topics cover NestJS across the Foundation 100.

Module 2 · Node.js & Express Foundations

Controllers

The layer that receives an HTTP request, coordinates the work, and returns a response, while delegating the actual business logic to services.

intermediate2 min read

Services

The layer that holds an application’s business logic, kept separate from the HTTP layer so rules live in one place and can be reused and tested directly.

intermediate2 min read

Dependency Injection

A design pattern where an object receives its collaborators from outside rather than creating them itself, making code looser-coupled and far easier to test.

Module 4 · API Design & Backend Patterns

intermediate2 min read

DTOs

Data Transfer Objects define the exact shape of data crossing an API boundary, giving each request and response an explicit, validated contract.

intermediate2 min read

Serialization

Converting in-memory objects into a transferable format such as JSON, and controlling exactly which fields are exposed so internal data never leaks.

intermediate2 min read

Repository Pattern

A pattern that puts all data access for an entity behind a dedicated interface, so business logic works with a collection-like abstraction instead of raw queries.

intermediate2 min read

Exception Filters

A centralised mechanism that catches errors thrown anywhere in request handling and turns them into consistent, safe HTTP responses.

Module 10 · Software Engineering & Architecture

intermediate2 min read

Layered Architecture

Organising an application into horizontal layers — presentation, business logic, and data access — each with a clear responsibility and a one-directional flow.

Projects using NestJS

Practice NestJS on real Padlor projects — coming soon.