Fluent validation and asp net core 6 web api


ASP.NET is a popular programming language used for web applications. It provides a framework for developing dynamic websites, web services, and web APIs. In this article, we will explore how to use Fluent with ASP.NET Core 6 Web API.

What is Fluent Validation?

Fluent Validation is a .NET library that provides a fluent interface for validating objects. It allows you to define validation rules in a clear and concise manner, it easier to maintain and understand your validation logic.

Setting up ASP.NET Core 6 Web API

Before we can start Fluent Validation, we need to set up an ASP.NET Core 6 Web API project. Here's a basic example of how to create a new Web API project:

dotnet new webapi -n MyWebApi
cd MyWebApi
dotnet run

This will create a new ASP.NET Core 6 Web API project named “MyWebApi” and run it .

Installing Fluent Validation

To use Fluent Validation in our ASP.NET Core 6 Web API project, we need to install the . NuGet package. Open a command prompt or terminal and navigate to the root directory of your project. Then, run the following command:

dotnet add package FluentValidation.AspNetCore

This will install the FluentValidation.AspNetCore package and add it as a dependency to your project.

Creating a Validator

Once Fluent Validation is installed, we can start creating validators for our models. A validator is a class that defines the validation rules for a specific model. Here's an example of how to create a validator for a “Person” model:

In this example, we define two validation rules for the “Name” and “Age” properties of the “Person” model. The “NotEmpty” rule ensures that the “Name” property is not empty, and the “GreaterThan” rule ensures that the “Age” property is greater than 0.

Using the Validator in a Controller

Once we have created a validator, we can use it in our controller to validate incoming requests. Here's an example of how to use the “PersonValidator” in a controller action:

public IActionResult CreatePerson(Person person)
    var validator = new PersonValidator();
    var validationResult = validator.Validate(person);

    if (!validationResult.IsValid)

    // Process the valid request
    return Ok();

In this example, we create an of the “PersonValidator” and use it to validate the “person” object. If the validation fails, we return a BadRequest response with the validation errors. Otherwise, we process the valid request.


Fluent Validation is a powerful library that simplifies the process of validating objects in ASP.NET Core 6 Web API. By using Fluent Validation, you can define clear and concise validation rules for your models, making your code more and easier to understand.

By following the steps outlined in this article, you should now have a good understanding of how to use Fluent Validation with ASP.NET Core 6 Web API. Start exploring the possibilities of Fluent Validation and enhance the validation capabilities of your web applications.

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