FluentValidation 12.0.0

Prefix Reserved
.NET 8.0 This package targets .NET 8.0. The package is compatible with this framework or higher. 
dotnet add package FluentValidation --version 12.0.0
                    


                    

                
NuGet\Install-Package FluentValidation -Version 12.0.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="FluentValidation" Version="12.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="FluentValidation" Version="12.0.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="FluentValidation" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add FluentValidation --version 12.0.0
                    


                    

                
#r "nuget: FluentValidation, 12.0.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package FluentValidation@12.0.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=FluentValidation&version=12.0.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=FluentValidation&version=12.0.0
                    


                            Install as a Cake Tool

FluentValidation is validation library for .NET that uses a fluent interface and lambda expressions for building strongly-typed validation rules.

Supporting the project

If you use FluentValidation in a commercial project, please sponsor the project financially. FluentValidation is developed and supported by @JeremySkinner for free in his spare time and financial sponsorship helps keep the project going. You can sponsor the project via either GitHub sponsors or OpenCollective.

Example

With FluentValidation, you can define a class that inherits from AbstractValidator which contains the rules for a particular class. The example below shows how you could define rules for a Customer class, and then how to execute the validator.

using FluentValidation;

public class CustomerValidator: AbstractValidator<Customer> {
  public CustomerValidator() {
    RuleFor(x => x.Surname).NotEmpty();
    RuleFor(x => x.Forename).NotEmpty().WithMessage("Please specify a first name");
    RuleFor(x => x.Discount).NotEqual(0).When(x => x.HasDiscount);
    RuleFor(x => x.Address).Length(20, 250);
    RuleFor(x => x.Postcode).Must(BeAValidPostcode).WithMessage("Please specify a valid postcode");
  }

  private bool BeAValidPostcode(string postcode) {
    // custom postcode validating logic goes here
  }
}

var customer = new Customer();
var validator = new CustomerValidator();

// Execute the validator.
ValidationResult results = validator.Validate(customer);

// Inspect any validation failures.
bool success = results.IsValid;
List<ValidationFailure> failures = results.Errors;

Full Documentation

Full documentation can be found at https://docs.fluentvalidation.net

Release Notes and Change Log

Release notes can be found on GitHub.

Product Compatible and additional computed target framework versions.
.NET net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 was computed.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

  • net8.0

    • No dependencies.

NuGet packages (2.7K)

Showing the top 5 NuGet packages that depend on FluentValidation:

Package Downloads
FluentValidation.DependencyInjectionExtensions

Dependency injection extensions for FluentValidation
FluentValidation.AspNetCore

AspNetCore integration for FluentValidation
Ocelot

Ocelot is an API gateway based on .NET stack.
Reo.Core.Validation

Package Description
Reo.Core.DataModels

Package Description

GitHub repositories (247)

Showing the top 20 popular GitHub repositories that depend on FluentValidation:

Repository Stars
ardalis/CleanArchitecture
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abpframework/abp
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kgrzybek/modular-monolith-with-ddd
Full Modular Monolith application with Domain-Driven Design approach.
Sonarr/Sonarr
Smart PVR for newsgroup and bittorrent users.
Radarr/Radarr
Movie organizer/manager for usenet and torrent users.
aspnetboilerplate/aspnetboilerplate
ASP.NET Boilerplate - Web Application Framework
dotnet-architecture/eShopOnWeb
Sample ASP.NET Core 8.0 reference application, now community supported: https://github.com/NimblePros/eShopOnWeb
MudBlazor/MudBlazor
Blazor Component Library based on Material Design principles with an emphasis on ease of use and extensibility
ThreeMammals/Ocelot
.NET API Gateway
NancyFx/Nancy
Lightweight, low-ceremony, framework for building HTTP based services on .Net and Mono
EduardoPires/EquinoxProject
Web Application ASP.NET 9 using Clean Architecture, DDD, CQRS, Event Sourcing and a lot of good practices
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Windows tray utility / filesystem watcher / launcher for Syncthing
FastEndpoints/FastEndpoints
A light-weight REST API development framework for ASP.NET 8 and newer.
Prowlarr/Prowlarr
Prowlarr is an indexer manager/proxy built on the popular *arr .net/reactjs base stack to integrate with your various PVR apps, supporting management of both Torrent Trackers and Usenet Indexers.
jasontaylordev/NorthwindTraders
Northwind Traders is a sample application built using ASP.NET Core and Entity Framework Core.
Lidarr/Lidarr
Looks and smells like Sonarr but made for music.
microsoft/RulesEngine
A fast and reliable .NET Rules Engine with extensive Dynamic expression support
fullstackhero/blazor-starter-kit
Clean Architecture Template for Blazor WebAssembly Built with MudBlazor Components.
Megabit/Blazorise
Blazorise is a component library built on top of Blazor with support for CSS frameworks like Bootstrap, Tailwind, Bulma, AntDesign, and Material.
Readarr/Readarr
Book Manager and Automation (Sonarr for Ebooks)
Version Downloads Last Updated
12.0.0 8,362,917 5/5/2025
12.0.0-preview1 202,829 1/2/2025
11.11.0 35,686,811 11/16/2024
11.10.0 18,021,958 9/15/2024
11.9.2 24,669,808 6/10/2024
11.9.1 12,716,406 4/23/2024
11.9.0 31,391,761 12/21/2023
11.8.1 8,982,130 11/22/2023
11.8.0 9,295,331 10/19/2023
11.7.1 11,417,965 8/12/2023
11.7.0 133,572 8/11/2023
11.6.0 8,723,094 7/4/2023
11.5.2 19,210,793 4/7/2023
11.5.1 61,852,739 2/20/2023
11.5.0 2,969,415 2/13/2023
11.4.0 19,332,285 11/23/2022
11.3.0 3,615,902 11/10/2022
11.2.2 16,532,333 9/11/2022
11.2.1 23,123,879 8/28/2022
11.2.0 7,693,086 8/8/2022
11.1.1 664,443 8/6/2022
11.1.0 13,226,995 6/22/2022
11.0.3 3,559,871 6/10/2022
11.0.2 5,416,388 5/27/2022
11.0.1 6,747,753 5/7/2022
11.0.0 6,427,532 4/30/2022
10.4.0 20,711,482 3/11/2022
10.3.6 27,222,837 12/13/2021
10.3.5 3,224,492 11/30/2021
10.3.4 10,257,807 10/22/2021
10.3.3 12,038,731 8/24/2021
10.3.1 733,481 8/19/2021
10.3.0 8,488,677 7/9/2021
10.2.3 8,503,302 6/3/2021
10.2.2 465,630 6/1/2021
10.2.1 1,368,366 5/30/2021
10.2.0 387,123 5/28/2021
10.1.0 5,481,688 4/28/2021
10.0.4 4,232,592 4/17/2021
9.5.4 6,993,209 4/5/2021
9.5.3 4,066,061 3/15/2021
9.5.2 2,014,424 3/8/2021
9.5.1 6,777,988 2/11/2021
9.5.0 3,406,661 1/31/2021
9.4.0 3,109,045 1/14/2021
9.3.0 14,955,716 11/10/2020
9.3.0-preview3 39,760 10/19/2020
9.3.0-preview2 152,544 9/15/2020
9.3.0-preview1 13,508 8/26/2020
9.2.2 7,178,441 9/20/2020
9.2.1 32,036 9/19/2020
9.2.0 7,945,224 8/26/2020
9.1.3 1,031,763 8/19/2020
9.1.2 967,323 8/12/2020
9.1.1 672,903 8/8/2020
9.1.0 292,593 8/8/2020
9.0.1 5,489,049 7/14/2020
9.0.0-preview5 89,982 5/23/2020
9.0.0-preview4 141,808 4/22/2020
9.0.0-preview3 203,992 2/29/2020
9.0.0-preview2 32,475 2/21/2020
9.0.0-preview1 100,277 2/8/2020
8.6.3 7,633,879 8/28/2020
8.6.2 28,848,690 2/29/2020
8.6.1 13,053,977 12/28/2019
8.6.0 4,327,148 12/4/2019
8.5.1 3,878,572 11/2/2019
8.5.0 6,528,902 9/24/2019
8.5.0-preview5 70,050 9/1/2019
8.5.0-preview4 101,692 7/23/2019
8.5.0-preview3 32,088 7/10/2019
8.5.0-preview2 87,877 6/13/2019
8.5.0-preview1 63,116 5/10/2019
8.4.0 14,668,585 5/10/2019
8.3.0 4,111,630 4/24/2019
8.2.3 722,198 4/12/2019
8.2.2 1,110,690 4/5/2019
8.2.1 499,114 4/4/2019
8.2.0 1,088,354 3/26/2019
8.1.3 5,177,733 1/25/2019
8.1.2 2,379,157 12/18/2018
8.1.1 609,291 12/11/2018
8.1.0 810,044 12/6/2018
8.1.0-preview2 29,812 11/14/2018
8.1.0-preview1 28,086 10/14/2018
8.0.101 946,113 11/24/2018
8.0.100 4,095,167 9/4/2018
8.0.0 1,138,332 8/16/2018
8.0.0-rc1 54,222 7/24/2018
8.0.0-preview4 25,962 7/16/2018
8.0.0-preview3 24,544 7/13/2018
8.0.0-preview2 24,351 7/13/2018
7.6.105 1,813,531 8/11/2018
7.6.104 2,794,915 7/6/2018
7.6.103 1,312,660 6/16/2018
7.6.102 340,410 6/14/2018
7.6.101 77,635 6/13/2018
7.6.100 179,497 6/7/2018
7.6.0 406,326 6/1/2018
7.6.0-preview1 51,947 4/12/2018
7.5.2 3,954,378 3/16/2018
7.5.1 277,242 3/11/2018
7.5.0 752,713 2/26/2018
7.4.0 2,301,818 1/26/2018
7.3.4 1,122,737 1/2/2018
7.3.3 196,016 12/22/2017
7.3.2 75,915 12/21/2017
7.3.1 345,477 12/13/2017
7.3.0 123,873 12/13/2017
7.3.0-beta3 28,439 12/8/2017
7.3.0-beta2 47,218 11/20/2017
7.3.0-beta1 25,299 11/11/2017
7.2.1 2,917,813 10/24/2017
7.2.0 837,941 10/5/2017
7.2.0-beta3 41,703 9/5/2017
7.2.0-beta2 27,518 8/22/2017
7.2.0-beta1 23,738 8/19/2017
7.1.1 2,310,243 7/25/2017
7.1.0 560,019 6/28/2017
7.1.0-beta1 23,494 6/24/2017
7.0.3 760,519 6/7/2017
7.0.2 288,625 5/26/2017
7.0.1 94,475 5/23/2017
7.0.0 739,881 5/19/2017
7.0.0-beta3 41,401 5/1/2017
7.0.0-beta2 27,184 4/17/2017
7.0.0-beta1 24,755 4/7/2017
6.4.1 2,102,386 3/15/2017
6.4.1-beta1 23,861 3/13/2017
6.4.0 1,043,727 3/3/2017
6.4.0-rc4 146,523 2/13/2017
6.4.0-rc3 39,543 2/3/2017
6.4.0-rc2 39,847 1/30/2017
6.4.0-rc1 23,634 1/30/2017
6.4.0-beta9 91,286 11/21/2016
6.4.0-beta8 50,650 10/31/2016
6.4.0-beta7 24,269 10/28/2016
6.4.0-beta6 24,580 10/25/2016
6.4.0-beta5 24,166 10/24/2016
6.4.0-beta4 24,272 10/21/2016
6.4.0-beta3 71,502 7/4/2016
6.4.0-beta2 25,164 7/1/2016
6.4.0-beta10 23,370 1/30/2017
6.4.0-beta1 28,467 6/28/2016
6.3.4-alpha 426,594 6/1/2016
6.3.3-alpha 23,176 5/27/2016
6.2.1 5,397,079 2/26/2016
6.2.1-beta1 28,613 2/24/2016
6.2.0 171,513 2/22/2016
6.2.0-beta1 24,460 2/12/2016
6.1.0 432,430 1/18/2016
6.0.2 116,832 1/5/2016
6.0.1 39,955 1/5/2016
6.0.0 133,989 12/22/2015
5.6.2 1,605,562 5/29/2015
5.6.1 34,678 5/29/2015
5.5.0 1,213,074 10/31/2014
5.4.0 609,281 7/3/2014
5.3.0 105,358 5/27/2014
5.2.0 76,497 5/21/2014
5.1.0 1,050,659 3/11/2014
5.0.0.1 549,055 10/24/2013
4.0.0.1 303,488 7/18/2013
4.0.0 119,572 4/29/2013
3.4.6 418,063 8/30/2012
3.4.0 71,371 8/17/2012
3.3.1 92,099 3/30/2012
3.2.0 77,129 11/14/2011
3.1.0 53,074 7/30/2011
3.0.0.1 26,415 7/5/2011
3.0.0 47,062 6/25/2011
2.0.0 76,528 1/9/2011
1.3.0 403,358 1/7/2011

FluentValidation 12 is a major release. Please read the upgrade guide at https://docs.fluentvalidation.net/en/latest/upgrading-to-12.html

Full release notes can be found at https://github.com/FluentValidation/FluentValidation/releases