How to install CurlDotNet for PowerShell and C#

To install CurlDotNet for PowerShell, download the CurlDotNet package from nuget.org, extract it, and load the DLL that matches your PowerShell runtime with Add-Type -Path. For C# projects use dotnet add package CurlDotNet, and for scripts use #r "nuget: CurlDotNet".

C# projects

dotnet add package CurlDotNet

C# scripts (.csx) and .NET 10 file-based apps

With dotnet-script:

#r "nuget: CurlDotNet, 9.8.0"
using CurlDotNet;

Console.WriteLine(Curl.Execute("curl https://httpbin.org/get").StatusCode);

With the .NET 10 SDK, a single .cs file can reference the package directly. Save this as app.cs and run dotnet run app.cs:

#:package CurlDotNet@9.8.0
using CurlDotNet;

var result = await Curl.ExecuteAsync("curl https://httpbin.org/uuid");
Console.WriteLine(result.Body);

PowerShell: pick the right DLL

A .nupkg is a zip file with one DLL per target framework under lib/. Version 9.8.0 contains net472, net48, net8.0, net9.0, net10.0 and netstandard2.0. Load the one that matches the runtime PowerShell runs on:

PowerShell Runs on Load
PowerShell 7.4 .NET 8 lib/net8.0/CurlDotNet.dll
PowerShell 7.5 .NET 9 lib/net9.0/CurlDotNet.dll (or net8.0)
Windows PowerShell 5.1 .NET Framework 4.x lib/net48/CurlDotNet.dll (net472 if only 4.7.2 is installed)

To check what you are running, use $PSVersionTable.PSVersion and [System.Runtime.InteropServices.RuntimeInformation]::FrameworkDescription. On a runtime newer than the newest folder, use the newest folder that is not newer than the runtime.

PowerShell 7: download and load

$version = '9.8.0'
$root = Join-Path $HOME ".curldotnet/$version"
New-Item -ItemType Directory -Force -Path $root | Out-Null
$nupkg = Join-Path $root 'curldotnet.zip'
Invoke-WebRequest "https://api.nuget.org/v3-flatcontainer/curldotnet/$version/curldotnet.$version.nupkg" -OutFile $nupkg
Expand-Archive $nupkg -DestinationPath $root -Force

Add-Type -Path (Join-Path $root 'lib/net8.0/CurlDotNet.dll')
[CurlDotNet.Curl]::Execute('curl https://httpbin.org/get').StatusCode

Add the Add-Type line to your $PROFILE to load it in every session.

Windows PowerShell 5.1

The same steps, with two Windows PowerShell details:

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
$root = "$env:LOCALAPPDATA\curldotnet\9.8.0"
New-Item -ItemType Directory -Force -Path $root | Out-Null
Invoke-WebRequest 'https://api.nuget.org/v3-flatcontainer/curldotnet/9.8.0/curldotnet.9.8.0.nupkg' -OutFile "$root\curldotnet.zip" -UseBasicParsing
Expand-Archive "$root\curldotnet.zip" -DestinationPath $root -Force
Get-ChildItem $root -Recurse -Filter *.dll | Unblock-File
Add-Type -Path "$root\lib\net48\CurlDotNet.dll"

Expand-Archive in 5.1 only accepts a .zip extension, which is why the file is saved as curldotnet.zip. Unblock-File removes the downloaded-from-internet mark that can stop .NET Framework from loading the DLL.

Alternative: Install-Package (PackageManagement)

Register-PackageSource -Name nuget.org -Location https://www.nuget.org/api/v2 -ProviderName NuGet -Trusted
Install-Package CurlDotNet -Source nuget.org -Scope CurrentUser -SkipDependencies
$pkgDir = Split-Path (Get-Package CurlDotNet).Source
Add-Type -Path (Join-Path $pkgDir 'lib/net8.0/CurlDotNet.dll')

-SkipDependencies avoids pulling the package’s NuGet dependencies, which basic curl execution does not need on .NET 8+ (see below). Skip Register-PackageSource if Get-PackageSource already lists a NuGet source for nuget.org.

Dependencies

On .NET 8 and later, loading CurlDotNet.dll on its own was enough to run requests, read headers and generate code in our test. The netstandard2.0 build uses Newtonsoft.Json for ParseJson and AsJsonDynamic. In PowerShell you can avoid those helpers entirely by piping .Body to ConvertFrom-Json.

What was and was not verified