reCAPTCHA Enterprise API C++ Client Library

An idiomatic C++ client library for the reCAPTCHA Enterprise API. This service helps protect your website from fraudulent activity, spam, and abuse without creating friction.

While this library is GA, please note that the Google Cloud C++ client libraries do not follow Semantic Versioning.


The following shows the code that you'll run in the google/cloud/recaptchaenterprise/quickstart/ directory, which should give you a taste of the reCAPTCHA Enterprise API C++ client library API.

#include "google/cloud/recaptchaenterprise/v1/recaptcha_enterprise_client.h"
#include "google/cloud/project.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  if (argc != 2) {
    std::cerr << "Usage: " << argv[0] << " project-id\n";
    return 1;

  namespace recaptchaenterprise = ::google::cloud::recaptchaenterprise_v1;
  auto client = recaptchaenterprise::RecaptchaEnterpriseServiceClient(

  auto const project = google::cloud::Project(argv[1]);
  for (auto r : client.ListKeys(project.FullName())) {
    if (!r) throw std::move(r).status();
    std::cout << r->DebugString() << "\n";

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;

Main classes

The main class in this library is recaptchaenterprise_v1::RecaptchaEnterpriseServiceClient. All RPCs are exposed as member functions of this class. Other classes provide helpers, configuration parameters, and infrastructure to mock recaptchaenterprise_v1::RecaptchaEnterpriseServiceClient when testing your application.

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