Modules are used to organize your application into separate, reusable parts.

As your project grows, you will create multiple controllers and services. Instead of keeping everything in one place, modules allow you to group related functionality together.

Every Nest.js application has at least one module:

app.module.ts

This is the root module. It is the starting point of your application and connects all other modules.

A module looks like this:

import { Module } from '@nestjs/common';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

@Module({
  imports: [],
  controllers: [UsersController],
  providers: [UsersService],
})
export class AppModule {}

Here is what each property does:

• controllers registers the controllers used by this module;
• providers registers the services available for dependency injection;
• imports allows the module to use functionality from other modules.

Modules help you:

• Group related features together;
• Keep your application organized;
• Make your code easier to maintain as the project grows.

Instead of placing every controller and service inside a single file, Nest.js encourages you to organize your application into logical feature-based modules.