FluentValidation

Overview

FluentValidation provides a fluent interface for building validation rules in .NET applications. This skill should be invoked when validating input models, commands, DTOs, or implementing complex validation logic with clean, readable code.

Core Principles

• Fluent API: Chain validation rules for readability
• Separation: Keep validators in dedicated classes
• Composition: Combine validators with And/Or
• Integration: Works seamlessly with MediatR

Preparation Checklist

• Install FluentValidation: dotnet add package FluentValidation
• Install ASP.NET integration: dotnet add package FluentValidation.AspNetCore
• Plan validation for each input model
• Set up dependency injection