Summary  
This chapter explains how to define dynamic URL segments as route parameters in route decorators and extract their values in controller methods using parameter decorators.  

General domain of usage  
Web API endpoints



Route parameters allow you to pass dynamic values in the URL.

For example, instead of requesting all users, you can request a specific user by ID.

Define a route parameter like this:

```ts 
import { Controller, Get, Param } from '@nestjs/common';

@Controller('users')
export class UsersController {
  @Get(':id')
  getUserById(@Param('id') id: string) {
    return `User ID: ${id}`;
  }
}
```

<br>

* `:id`: defines a dynamic part of the URL;
* `@Param('id')`: extracts the value from the URL;
* `id`: is passed into the method.

When you open:

```bash 
/users/5
```

The response will be:

```bash 
User ID: 5
```

You can use route parameters whenever you need to work with specific data, such as users, products, or orders.


What decorator is used to access route parameters in Nest.js?

Learn how to build structured backend applications with Nest.js. Organize your code using controllers, services, and modules, handle requests and data validation, and create a complete API using a scalable architecture.

Set up your first Nest.js application and understand how it is structured. Learn how the main files work together to handle requests and organize backend logic.

Learn how to handle requests in Nest.js using controllers and routes. Define endpoints, work with route and query parameters, and control how your backend responds to client requests.

Learn how to organize backend logic using services. Move business logic out of controllers, structure your code properly, and understand how different parts of your application work together.

Learn how Nest.js organizes applications using modules and dependency injection. Understand how different parts of your backend connect and how to structure your code into scalable, maintainable features.

Learn how to handle and validate data in Nest.js. Work with request body data, define structured DTOs, and ensure incoming data is correct using validation pipes.

Summarize what you have learned throughout the track and reinforce your understanding of backend development. Review key concepts and see how they come together into a complete, structured application.

Working with Route Parameters