FluentValidation 9.0.0-preview1

Prefix Reserved
.NET Standard 2.0 This package targets .NET Standard 2.0. The package is compatible with this framework or higher. .NET Framework 4.6.1 This package targets .NET Framework 4.6.1. The package is compatible with this framework or higher.
This is a prerelease version of FluentValidation.
There is a newer version of this package available.
See the version list below for details. 
dotnet add package FluentValidation --version 9.0.0-preview1
                    


                    

                
NuGet\Install-Package FluentValidation -Version 9.0.0-preview1
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="9.0.0-preview1" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="FluentValidation" Version="9.0.0-preview1" />
                    


                            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 9.0.0-preview1
                    


                    

                
#r "nuget: FluentValidation, 9.0.0-preview1"
#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@9.0.0-preview1
#: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=9.0.0-preview1&prerelease
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=FluentValidation&version=9.0.0-preview1&prerelease
                    


                            Install as a Cake Tool

FluentValidation 9 is a major release. Please read the upgrade notes at https://docs.fluentvalidation.net/en/latest/upgrading-to-9.html

Changes in 9.0.0:

  • Removed support for netstandard1.1 and netstandard1.6
  • Default email validation mode now uses the same logic as ASP.NET Core. Previous regex behaviour is opt-in.
  • TestHelper advanced mode now has more features (see https://docs.fluentvalidation.net/en/latest/testing.html#advanced-test-extensions)
  • Equal/NotEqual now perform ordinal comparison when used with string properties
  • Severity can now be set dynamically with a callback
  • Removed WithLocalizedMessage (WithMessage that takes a callback is the replacement)
  • Removed ResourceName from ValidationFailure
  • Removed ResourceName and ResourceType from IStringSource.
  • Removed SetCollectionValidator which was deprecated in 8.0
  • Additional overload of OnAnyFailure that can receive a collection of validation failures
  • Remove DisplayAttribute integration and reference to DataAnnotations.
  • ComparisonProperty placeholder is now formatted like PropertyName
  • Translations of default error messages into other languages are now lazily-loaded

Full release notes can be found at https://github.com/JeremySkinner/FluentValidation/blob/master/Changelog.txt

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  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. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 is compatible.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

  • .NETFramework 4.6.1

    • No dependencies.

  • .NETStandard 2.0

    • No dependencies.

NuGet packages (2.8K)

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 (253)

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

Repository Stars
ardalis/CleanArchitecture
Clean Architecture Solution Template: A proven Clean Architecture Template for ASP.NET Core 9
abpframework/abp
Open-source web application framework for ASP.NET Core! Offers an opinionated architecture to build enterprise software solutions with best practices on top of the .NET. Provides the fundamental infrastructure, cross-cutting-concern implementations, startup templates, application modules, UI themes, tooling and documentation.
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
canton7/SyncTrayzor
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 16,255,312 5/5/2025
12.0.0-preview1 239,009 1/2/2025
11.11.0 45,183,236 11/16/2024
11.10.0 20,284,704 9/15/2024
11.9.2 27,043,079 6/10/2024
11.9.1 13,869,787 4/23/2024
11.9.0 33,694,972 12/21/2023
11.8.1 9,732,013 11/22/2023
11.8.0 9,881,279 10/19/2023
11.7.1 12,046,256 8/12/2023
11.7.0 141,150 8/11/2023
11.6.0 9,172,747 7/4/2023
11.5.2 20,182,031 4/7/2023
11.5.1 67,051,544 2/20/2023
11.5.0 3,148,584 2/13/2023
11.4.0 20,115,615 11/23/2022
11.3.0 3,761,443 11/10/2022
11.2.2 17,136,107 9/11/2022
11.2.1 23,898,298 8/28/2022
11.2.0 7,869,713 8/8/2022
11.1.1 680,948 8/6/2022
11.1.0 13,622,230 6/22/2022
11.0.3 3,697,739 6/10/2022
11.0.2 5,630,374 5/27/2022
11.0.1 6,952,970 5/7/2022
11.0.0 6,939,654 4/30/2022
10.4.0 21,485,028 3/11/2022
10.3.6 28,000,516 12/13/2021
10.3.5 3,298,390 11/30/2021
10.3.4 10,549,390 10/22/2021
10.3.3 12,452,267 8/24/2021
10.3.1 752,023 8/19/2021
10.3.0 8,703,137 7/9/2021
10.2.3 8,722,068 6/3/2021
10.2.2 475,653 6/1/2021
10.2.1 1,392,164 5/30/2021
10.2.0 393,865 5/28/2021
10.1.0 5,610,899 4/28/2021
10.0.4 4,383,171 4/17/2021
9.5.4 7,509,166 4/5/2021
9.5.3 4,136,951 3/15/2021
9.5.2 2,060,073 3/8/2021
9.5.1 6,907,994 2/11/2021
9.5.0 3,481,757 1/31/2021
9.4.0 3,160,138 1/14/2021
9.3.0 15,229,614 11/10/2020
9.3.0-preview3 40,061 10/19/2020
9.3.0-preview2 154,174 9/15/2020
9.3.0-preview1 13,627 8/26/2020
9.2.2 7,295,138 9/20/2020
9.2.1 33,441 9/19/2020
9.2.0 8,103,334 8/26/2020
9.1.3 1,045,963 8/19/2020
9.1.2 988,224 8/12/2020
9.1.1 686,325 8/8/2020
9.1.0 313,483 8/8/2020
9.0.1 5,681,378 7/14/2020
9.0.0-preview5 90,515 5/23/2020
9.0.0-preview4 147,477 4/22/2020
9.0.0-preview3 208,142 2/29/2020
9.0.0-preview2 32,698 2/21/2020
9.0.0-preview1 101,065 2/8/2020
8.6.3 7,912,825 8/28/2020
8.6.2 29,431,356 2/29/2020
8.6.1 13,293,621 12/28/2019
8.6.0 4,401,874 12/4/2019
8.5.1 3,941,551 11/2/2019
8.5.0 6,721,142 9/24/2019
8.5.0-preview5 70,840 9/1/2019
8.5.0-preview4 102,928 7/23/2019
8.5.0-preview3 32,645 7/10/2019
8.5.0-preview2 89,235 6/13/2019
8.5.0-preview1 64,284 5/10/2019
8.4.0 15,027,224 5/10/2019
8.3.0 4,204,739 4/24/2019
8.2.3 739,604 4/12/2019
8.2.2 1,139,069 4/5/2019
8.2.1 505,295 4/4/2019
8.2.0 1,104,454 3/26/2019
8.1.3 5,238,502 1/25/2019
8.1.2 2,408,606 12/18/2018
8.1.1 619,516 12/11/2018
8.1.0 850,251 12/6/2018
8.1.0-preview2 29,892 11/14/2018
8.1.0-preview1 28,209 10/14/2018
8.0.101 960,901 11/24/2018
8.0.100 4,158,367 9/4/2018
8.0.0 1,173,211 8/16/2018
8.0.0-rc1 54,512 7/24/2018
8.0.0-preview4 26,114 7/16/2018
8.0.0-preview3 24,715 7/13/2018
8.0.0-preview2 24,567 7/13/2018
7.6.105 1,878,630 8/11/2018
7.6.104 2,833,727 7/6/2018
7.6.103 1,328,487 6/16/2018
7.6.102 344,129 6/14/2018
7.6.101 78,037 6/13/2018
7.6.100 181,321 6/7/2018
7.6.0 411,508 6/1/2018
7.6.0-preview1 52,885 4/12/2018
7.5.2 4,004,245 3/16/2018
7.5.1 282,535 3/11/2018
7.5.0 756,595 2/26/2018
7.4.0 2,380,715 1/26/2018
7.3.4 1,140,452 1/2/2018
7.3.3 199,437 12/22/2017
7.3.2 76,907 12/21/2017
7.3.1 349,703 12/13/2017
7.3.0 127,758 12/13/2017
7.3.0-beta3 28,582 12/8/2017
7.3.0-beta2 47,606 11/20/2017
7.3.0-beta1 25,418 11/11/2017
7.2.1 2,964,293 10/24/2017
7.2.0 851,891 10/5/2017
7.2.0-beta3 41,868 9/5/2017
7.2.0-beta2 27,680 8/22/2017
7.2.0-beta1 23,888 8/19/2017
7.1.1 2,401,298 7/25/2017
7.1.0 564,652 6/28/2017
7.1.0-beta1 23,663 6/24/2017
7.0.3 765,046 6/7/2017
7.0.2 291,883 5/26/2017
7.0.1 98,647 5/23/2017
7.0.0 756,621 5/19/2017
7.0.0-beta3 66,312 5/1/2017
7.0.0-beta2 27,336 4/17/2017
7.0.0-beta1 24,934 4/7/2017
6.4.1 2,215,667 3/15/2017
6.4.1-beta1 23,951 3/13/2017
6.4.0 1,072,540 3/3/2017
6.4.0-rc4 146,728 2/13/2017
6.4.0-rc3 39,902 2/3/2017
6.4.0-rc2 39,960 1/30/2017
6.4.0-rc1 23,760 1/30/2017
6.4.0-beta9 91,787 11/21/2016
6.4.0-beta8 50,763 10/31/2016
6.4.0-beta7 24,402 10/28/2016
6.4.0-beta6 24,702 10/25/2016
6.4.0-beta5 24,276 10/24/2016
6.4.0-beta4 24,377 10/21/2016
6.4.0-beta3 71,741 7/4/2016
6.4.0-beta2 25,274 7/1/2016
6.4.0-beta10 23,471 1/30/2017
6.4.0-beta1 28,670 6/28/2016
6.3.4-alpha 434,065 6/1/2016
6.3.3-alpha 23,264 5/27/2016
6.2.1 5,540,820 2/26/2016
6.2.1-beta1 28,743 2/24/2016
6.2.0 172,523 2/22/2016
6.2.0-beta1 24,595 2/12/2016
6.1.0 440,047 1/18/2016
6.0.2 118,102 1/5/2016
6.0.1 40,198 1/5/2016
6.0.0 135,653 12/22/2015
5.6.2 1,636,180 5/29/2015
5.6.1 34,998 5/29/2015
5.5.0 1,227,613 10/31/2014
5.4.0 613,675 7/3/2014
5.3.0 105,898 5/27/2014
5.2.0 77,068 5/21/2014
5.1.0 1,073,099 3/11/2014
5.0.0.1 563,277 10/24/2013
4.0.0.1 307,905 7/18/2013
4.0.0 121,042 4/29/2013
3.4.6 430,285 8/30/2012
3.4.0 72,302 8/17/2012
3.3.1 93,746 3/30/2012
3.2.0 78,537 11/14/2011
3.1.0 53,261 7/30/2011
3.0.0.1 26,531 7/5/2011
3.0.0 47,494 6/25/2011
2.0.0 77,897 1/9/2011
1.3.0 436,162 1/7/2011

FluentValidation 8 is a major release. Please read the upgrade notes at https://fluentvalidation.net/upgrading-to-8

Changes in 8.6.0:
* Add support for ASP.NET Core 3.1
* Fixed issue with property indexers being incorrectly stripped out when using test extensions.
* AddToModelState no longer includes a dot if PropertyName is null

Changes in 8.5.1:
* Ensure lazily loaded calls to WithMessage can be used for client-side validation, provided they don't attempt to access model properties from inside the delegate (eg when using IStringLocalizer).
* Fix issue where OnFailure didn't work properly when invoked on validators with conditions.

Changes in 8.5.0:
* Add additional overload of the EmailAddress validator for compatibility with ASP.NET Core's default email validation.
* Simplify the advanced testhelper syntax.
* Add support for ASP.NET Core 3.
* Add support for defining child rules inline.
* ValidatorDescriptor now has consistent handling of model-level rules.
* RuleForEach can now access collection index in error message with {CollectionIndex} placeholder.
* Welsh language translations of default error messages.
* Hungrian language translations of default error messages.
* Indonesian language translations of default error messages.
* Using RuleForEach combined with When is now more intuitive.
* Fixed order of rule execution when using async validation.

Changes in 8.4.0:
* Added simplified version of several messages across all translations to aid with ASP.NET Clientside validation.
* New enum validator for string properties.

Changes in 8.3.0:
* Fix issue in ASP.NET Core integration with GetServiceProvider not working correctly when invoked against a CustomContext/MessageBuilderContext.
* Improved how LanguageStringSource works with error-code overrides.
* Fix thread-safety issue with use of PropertyValidatorOptions.Empty (now removed).
* Improved how calls to When/Unless are handled internally.
* DelegatingValidator is now marked as deprecated.
* Improvements to Croatian language translations.
* Improvements to Georgian language translations.
* Resolved subtle bug where top-level WhenAsync wouldn't work correctly when wrapping a top-level call to When.

Changes in 8.2.3:
* Fix issue in WebApi integration where DataAnnotations validators could generate duplicate messages when in the same project as FluentValidation.

Changes in 8.2.2:
* Fix FluentValidation.DependencyInjection package name.

Changes in 8.2.1:
* Resolved issue using InjectValidator with RuleForEach.
* Add support for a default IValidatorInterceptor to be registered with the ASP.NET Core Service Provider.

Changes in 8.2.0:
* Add extensions for injecting child validators using the ASP.NET Core Service Provider.
* Implement RuleFor(...).ForEach(...) as an alternative to RuleForEach.
* WithLocalizedMessage is deprecated. Use the overload of WithMessage that takes a Func instead.

Changes in 8.1.3:
* Resolved issue where clientside validation was incorrectly generating metadata for rules with shared conditions.
* ScalePrecisionValidator now has a public method in the fluent interface.
* Fix placeholder names in ScalePrecisionValidator for consistency.
* Updates to Portuguese (Brazil) translations.

Changes in 8.1.2:
* Fix issue where shared When/Unless conditions didn't execute correctly when used with RuleForEach.

Changes in 8.1.1:
* Added RuleSetsExecuted property on ValidationResult.
* Resolved issue introduced in 8.1 where the shared condition cache does not work correctly with RuleForEach (#970).

Changes in 8.1:
* Add format support in message placeholders.
* Added support for overriding indexers for collection rules.
* Allow error codes to be used to override localization key in the Language Manager.
* Additional error details are now shown in the ShouldNotHaveValidationErrorFor test extension.
* Conditions defined with root-level When/WhenAsync/Unless/UnlessAsync are now only executed once (instead of once for each rule).
* Support Otherwise method chained from root-level When/WhenAsync/Unless/UnlessAsync.
* Minor wording changes to default English error messages.
* Japanese translation of the default error messages.
* Added Skip property to MVC5's CustomizeValidatorAttribute for parity with AspNetCore and WebApi.
* Remove type constraint on the OverridePropertyName overload that takes an expression.

Added Skip property to MVC5's CustomizeValidatorAttribute to bring parity with AspNetCore and WebApi integration.
Changes in 8.0:
* Support validating only specific properties by path.
* Added OnFailure method
* Deprecated RuleFor(..).SetCollectionValidator in favour of RuleForEach(...).SetValidator
* IStringSource.GetString now takes a validation context instead of a model instance.
* Introduce PropertyValidatorOptions in order to clean up the IPropretyValidator interface.
* Moved the legacy ValidatorAttribute and AttributedValidatorFactory into a separate FluentValidation.Attributes package.
* Remove the pre-7.0 localization mechanism
* Remove the pre-7.0 methods for custom validation
* Removed many other deprecated methods

Full release notes can be found at https://github.com/JeremySkinner/FluentValidation/blob/master/Changelog.txt