REST Sharp is a popular open-source library for consuming and working with RESTful APIs in .NET applications. It provides a simple and intuitive API for making HTTP requests, handling responses, and serializing/deserializing JSON and XML data.

In ASP.NET Core, you can use REST Sharp to interact with RESTful APIs from your web application. Here are the steps to get started:

1. Install the REST Sharp package: Begin by installing the REST Sharp package into your ASP.NET Core project. You can do this either via the NuGet Package Manager in Visual Studio or by using the Package Manager Console with the following command:

Install-Package RestSharp

1. Create a REST Sharp client: In your ASP.NET Core application, you'll typically create a REST Sharp client to handle the API requests. You can create an instance of the RestClient class and specify the base URL of the API you want to interact with. For example:

var client = new RestClient("https://api.example.com");

1. Define an API request: To make a specific API request, you need to create an instance of the RestRequest class. This allows you to set the HTTP method, request headers, parameters, and body content. Here's an example of creating a GET request:

var request = new RestRequest("/users/{id}", Method.GET);
request.AddUrlSegment("id", "123"); // Replace {id} placeholder with the actual user ID

1. Execute the request: Once you have defined the request, you can execute it using the REST Sharp client. You can use methods like Execute, ExecuteAsync, or Execute<T> (to deserialize the response into a specific type). Here's an example:

var response = client.Execute(request);

1. Handle the response: After executing the request, you can access the response details, such as the status code, headers, and content. Here's an example of reading the response content as a JSON string:

int statusCode = (int)response.StatusCode;
string content = response.Content;

1. Deserialize the response: If the response contains JSON or XML data, you can use REST Sharp's built-in deserialization capabilities to convert the response content into objects. You can use the DeserializeObject method or specify the expected type with the Execute<T> method. Here's an example of deserializing a JSON response into a custom class:

var user = JsonConvert.DeserializeObject<User>(response.Content);

These are the basic steps to get started with REST Sharp in ASP.NET Core. You can explore further by checking out the REST Sharp documentation for more advanced features and customization options.