Polyfill 10.3.0

.NET 5.0 This package targets .NET 5.0. The package is compatible with this framework or higher. .NET Core 2.0 This package targets .NET Core 2.0. The package is compatible with this framework or higher. .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. 
dotnet add package Polyfill --version 10.3.0
                    


                    

                
NuGet\Install-Package Polyfill -Version 10.3.0
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="Polyfill" Version="10.3.0">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Polyfill" Version="10.3.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Polyfill">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>
                    


                            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 Polyfill --version 10.3.0
                    


                    

                
#r "nuget: Polyfill, 10.3.0"
#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 Polyfill@10.3.0
#: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=Polyfill&version=10.3.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Polyfill&version=10.3.0
                    


                            Install as a Cake Tool

Polyfill

Source only package that exposes newer .NET and C# features to older runtimes.

The package targets netstandard2.0 and is designed to support the following runtimes.

  • net461, net462, net47, net471, net472, net48, net481
  • netcoreapp2.0, netcoreapp2.1, netcoreapp3.0, netcoreapp3.1
  • net5.0, net6.0, net7.0, net8.0, net9.0, net10.0, net11.0
  • uap10

Usage

After installing the NuGet package, polyfilled types and extension methods are available automatically. No extra using statements are needed beyond what the newer API requires.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Polyfill" Version="*" PrivateAssets="all" />
  </ItemGroup>
</Project>

Key Features

  • Source only — compiles directly into the consuming project, no runtime dependency.
  • 881 polyfilled APIs across attributes, extension methods, and static helpers.
  • Conditional compilation — only the APIs missing from the target framework are included.
  • Optional feature groups — Ensure, Guard, Nullability, ArgumentExceptions, StringInterpolation.

Documentation

See the full documentation on GitHub for the complete API list, configuration options, and troubleshooting.

A compiled library variant is also available: PolyfillLib

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Product Compatible and additional computed target framework versions.
.NET net5.0 is compatible.  net5.0-windows was computed.  net6.0 is compatible.  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 is compatible.  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 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 is compatible.  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 is compatible.  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.  net11.0 is compatible. 
.NET Core netcoreapp2.0 is compatible.  netcoreapp2.1 is compatible.  netcoreapp2.2 is compatible.  netcoreapp3.0 is compatible.  netcoreapp3.1 is compatible. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 is compatible. 
.NET Framework net461 is compatible.  net462 is compatible.  net463 was computed.  net47 is compatible.  net471 is compatible.  net472 is compatible.  net48 is compatible.  net481 is compatible. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Universal Windows Platform uap was computed.  uap10.0 is compatible. 
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.

This package has no dependencies.

NuGet packages (49)

Showing the top 5 NuGet packages that depend on Polyfill:

Package Downloads
vies-dotnet-api

European VIES VAT validation for dotnet.
ktsu.Extensions

A collection of useful extension methods for .NET types including strings, collections, dictionaries, enumerables, and reflection.
ktsu.AppDataStorage

A .NET library for persistent application data storage using JSON serialization. Provides a simple inherit-and-use pattern with automatic file management, thread-safe operations, debounced saves, backup recovery, and singleton access. Stores data in the user's app data folder with support for custom subdirectories and file names.
ktsu.CaseConverter

A library with extension methods to convert strings between common casings used in code.
ktsu.FuzzySearch

Lightweight .NET fuzzy string matching library with intelligent scoring for search-as-you-type, command palettes, and flexible string matching applications.

GitHub repositories (48)

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

Repository Stars
MaterialDesignInXAML/MaterialDesignInXamlToolkit
Google's Material Design in XAML & WPF, for C# & VB.Net.
spectreconsole/spectre.console
A .NET library that makes it easier to create beautiful console applications.
Humanizr/Humanizer
Humanizer meets all your .NET needs for manipulating and displaying strings, enums, dates, times, timespans, numbers and quantities
ClosedXML/ClosedXML
ClosedXML is a .NET library for reading, manipulating and writing Excel 2007+ (.xlsx, .xlsm) files. It aims to provide an intuitive and user-friendly interface to dealing with the underlying OpenXML API.
akkadotnet/akka.net
Canonical actor model implementation for .NET with local + distributed actors in C# and F#.
cyanfish/naps2
Scan documents to PDF and more, as simply as possible.
thomhurst/TUnit
A modern, fast and flexible .NET testing framework
VerifyTests/Verify
Verify is a snapshot testing tool that simplifies the assertion of complex data models and documents.
shouldly/shouldly
Should testing for .NET—the way assertions should be!
ardalis/Specification
Base class with tests for adding specifications to a DDD model
MichaelGrafnetter/DSInternals
Directory Services Internals (DSInternals) PowerShell Module and Framework
andrewlock/StronglyTypedId
A Rosyln-powered generator for strongly-typed IDs
ikvmnet/ikvm
A Java Virtual Machine and Bytecode-to-IL Converter for .NET
MarimerLLC/csla
A home for your business logic in any .NET application.
Mr-sans-and-InitLoader-s-team/Escape-From-Duckov-Coop-Mod-Preview
逃离鸭科夫联机mod（by Mr.sans & InitLoader）
andrewlock/NetEscapades.EnumGenerators
A source generator for generating fast "reflection" methods for enums
mattjohnsonpint/TimeZoneConverter
Lightweight libraries to convert between IANA, Windows, Rails, and POSIX time zones.
SnapXL/SnapX
SnapX is a free, open-source, cross-platform tool that lets you capture or record any area of your screen and instantly share it with a single keypress. Upload images, videos, text, and more to multiple supported destinations—all with ease. ShareX fork
andrewlock/NetEscapades.AspNetCore.SecurityHeaders
Small package to allow adding security headers to ASP.NET Core websites
getsentry/sentry-dotnet
Sentry SDK for .NET
Version Downloads Last Updated
10.3.0 29,496 4/11/2026
10.2.0 2,246 4/10/2026
10.1.1 2,979 4/9/2026
10.1.0 358 4/9/2026
10.0.0 5,683 4/5/2026
9.24.1 3,720 4/4/2026
9.24.1-beta.1 64 4/4/2026
9.24.0 3,016 4/3/2026
9.23.0 16,453 3/24/2026
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9.21.0 887 3/15/2026
9.20.0 1,806 3/14/2026
9.18.0 14,440 3/5/2026
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9.16.0 1,037 3/4/2026
9.15.0 1,844 3/3/2026
9.14.0 1,167 3/3/2026
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