GoogleReCaptcha.V3 1.3.1

dotnet add package GoogleReCaptcha.V3 --version 1.3.1
NuGet\Install-Package GoogleReCaptcha.V3 -Version 1.3.1
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="GoogleReCaptcha.V3" Version="1.3.1" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add GoogleReCaptcha.V3 --version 1.3.1
#r "nuget: GoogleReCaptcha.V3, 1.3.1"
#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.
// Install GoogleReCaptcha.V3 as a Cake Addin
#addin nuget:?package=GoogleReCaptcha.V3&version=1.3.1

// Install GoogleReCaptcha.V3 as a Cake Tool
#tool nuget:?package=GoogleReCaptcha.V3&version=1.3.1


Library for Google's ReCaptcha v3 backend

Target platform: .NET Core 3.1+

When targeting Core 3.0 use package version 1.1.2


Task<bool> IsCaptchaPassedAsync(string token);
Task<JObject> GetCaptchaResultDataAsync(string token);
void UpdateSecretKey(string key);

Setup guide

Install the package using nuget Update your appsetting.json config file

"googleReCaptcha:SiteKey": "YOUR_SITE_KEY",
"googleReCaptcha:SecretKey": "YOUR_SECRET_KEY"
"googleReCaptcha:SecretKey": "YOUR_MINIMUM_ACCEPTABLE_SCORE"

You can get your keys here:

Update your middleware

services.AddHttpClient<ICaptchaValidator, GoogleReCaptchaValidator>();

Update your Views

@inject Microsoft.Extensions.Configuration.IConfiguration Configuration

<form asp-action="FormPost">
    <input type="hidden" name="captcha" id="captchaInput" value=""/>

@section Scripts
    <script src="["googleReCaptcha:SiteKey"]"></script>
    grecaptcha.ready(function() {
        grecaptcha.execute('@Configuration["googleReCaptcha:SiteKey"]', { action: 'contact' }).then(function (token) {

Update your controller

inject ICaptchaValidator

public class HomeController : Controller
  private readonly ICaptchaValidator _captchaValidator;
  public HomeController(ICaptchaValidator captchaValidator)
      _captchaValidator = captchaValidator;
  public async Task<IActionResult> FormPost(Model collection, string captcha){
    if (!await _captchaValidator.IsCaptchaPassedAsync(captcha))
        ModelState.AddModelError("captcha","Captcha validation failed");
    return View(collection)

Additional info

You can use following method instead to get all response data

async Task<JObject> GetCaptchaResultDataAsync(string token)

To update secret key there is method.

void UpdateSecretKey(string key);

Method must be called jsut before the validation await _captchaValidator.IsCaptchaPassedAsync(captcha) after the form has been sent like this:

public async Task<IActionResult> Register(SampleViewModel collection, string captcha)
    _captchaValidator.UpdateSecretKey("NEW SECRET KEY");
    if (!await _captchaValidator.IsCaptchaPassedAsync(captcha))
        ModelState.AddModelError("captcha","Captcha validation failed");
        ViewData["Message"] = "Success";
    return View(collection);


Methods can throw 'HttpRequestException' when connection to the Google's service doesn't work or service doesn't response with HTTP 200


Contact me in case you find any errors or problem via email

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. 
.NET Core netcoreapp3.1 is compatible. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (1)

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A simple web application for devBetter
Version Downloads Last updated
1.3.1 166,799 5/31/2021
1.3.0 91,646 8/6/2020
1.2.0 7,908 5/28/2020
1.1.2 15,913 11/6/2019
1.1.1 850 11/5/2019
1.1.0 539 11/5/2019
1.0.0 637 11/5/2019

Added support for minimum score.