An idiomatic C++ client library for theRetail API. Cloud Retail service enables customers to build end-to-end personalized recommendation systems without requiring a high level of expertise in machine learning, recommendation system, or Google Cloud.
While this library isGA, please note Google Cloud C++ client libraries donotfollowSemantic Versioning.
Quickstart
The following shows the code that you'll run in thegoogle/cloud/retail/quickstart/directory, which should give you a taste of the Retail API C++ client library API.
#include "google/cloud/retail/v2/catalog_client.h"
#include <iostream>
int main(int argc, char* argv[]) try {
if (argc != 2) {
std::cerr << "Usage: " << argv[0] << " project-id\n";
return 1;
}
namespace retail = ::google::cloud::retail_v2;
auto client =
retail::CatalogServiceClient(retail::MakeCatalogServiceConnection());
// The service only accepts "global" as the location for ListCatalogs()
auto const location =
"projects/" + std::string(argv[1]) + "/locations/global";
for (auto r : client.ListCatalogs(location)) {
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
This library offers multiple*Clientclasses, which are listed below. Each one of these classes exposes all the RPCs for a gRPCserviceas member functions of the class. This library groups multiple gRPC services because they are part of the same product or are often used together. A typical example may be the administrative and data plane operations for a single product.
The library also has other classes that provide helpers, configuration parameters, and infrastructure to mock the*Clientclasses when testing your application.
The library automatically retries requests that fail with transient errors, and usesexponential backoffto backoff between retries. Application developers can override the default policies.
More Information
Error Handling- describes how the library reports errors.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis webpage provides documentation for the Retail API C++ client library, which enables the building of personalized recommendation systems without extensive machine learning expertise.\u003c/p\u003e\n"],["\u003cp\u003eThe library is currently generally available (GA), but it is important to note that it does not follow Semantic Versioning.\u003c/p\u003e\n"],["\u003cp\u003eThe library includes multiple \u003ccode\u003e*Client\u003c/code\u003e classes like \u003ccode\u003eCatalogServiceClient\u003c/code\u003e, \u003ccode\u003eCompletionServiceClient\u003c/code\u003e, \u003ccode\u003ePredictionServiceClient\u003c/code\u003e, \u003ccode\u003eProductServiceClient\u003c/code\u003e, \u003ccode\u003eSearchServiceClient\u003c/code\u003e, and \u003ccode\u003eUserEventServiceClient\u003c/code\u003e, each corresponding to gRPC services.\u003c/p\u003e\n"],["\u003cp\u003eThe library automatically manages retries for transient errors with exponential backoff, and allows developers to override default policies and other settings via the documentation provided.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, but this page also covers versions going as far back as 2.11.0.\u003c/p\u003e\n"]]],[],null,["Version 2.12.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/retail/latest)\n- [2.41.0](/cpp/docs/reference/retail/2.41.0)\n- [2.40.0](/cpp/docs/reference/retail/2.40.0)\n- [2.39.0](/cpp/docs/reference/retail/2.39.0)\n- [2.38.0](/cpp/docs/reference/retail/2.38.0)\n- [2.37.0](/cpp/docs/reference/retail/2.37.0)\n- [2.36.0](/cpp/docs/reference/retail/2.36.0)\n- [2.35.0](/cpp/docs/reference/retail/2.35.0)\n- [2.34.0](/cpp/docs/reference/retail/2.34.0)\n- [2.33.0](/cpp/docs/reference/retail/2.33.0)\n- [2.32.0](/cpp/docs/reference/retail/2.32.0)\n- [2.31.0](/cpp/docs/reference/retail/2.31.0)\n- [2.30.0](/cpp/docs/reference/retail/2.30.0)\n- [2.29.0](/cpp/docs/reference/retail/2.29.0)\n- [2.28.0](/cpp/docs/reference/retail/2.28.0)\n- [2.27.0](/cpp/docs/reference/retail/2.27.0)\n- [2.26.0](/cpp/docs/reference/retail/2.26.0)\n- [2.25.1](/cpp/docs/reference/retail/2.25.1)\n- [2.24.0](/cpp/docs/reference/retail/2.24.0)\n- [2.23.0](/cpp/docs/reference/retail/2.23.0)\n- [2.22.1](/cpp/docs/reference/retail/2.22.1)\n- [2.21.0](/cpp/docs/reference/retail/2.21.0)\n- [2.20.0](/cpp/docs/reference/retail/2.20.0)\n- [2.19.0](/cpp/docs/reference/retail/2.19.0)\n- [2.18.0](/cpp/docs/reference/retail/2.18.0)\n- [2.17.0](/cpp/docs/reference/retail/2.17.0)\n- [2.16.0](/cpp/docs/reference/retail/2.16.0)\n- [2.15.1](/cpp/docs/reference/retail/2.15.1)\n- [2.14.0](/cpp/docs/reference/retail/2.14.0)\n- [2.13.0](/cpp/docs/reference/retail/2.13.0)\n- [2.12.0](/cpp/docs/reference/retail/2.12.0)\n- [2.11.0](/cpp/docs/reference/retail/2.11.0) \n\nRetail API C++ Client Library\n=============================\n\nAn idiomatic C++ client library for the [Retail API](https://cloud.google.com/retail/docs). Cloud Retail service enables customers to build end-to-end personalized recommendation systems without requiring a high level of expertise in machine learning, recommendation system, or Google Cloud.\n\nWhile this library is **GA** , please note Google Cloud C++ client libraries do **not** follow [Semantic Versioning](https://semver.org/).\n\n### Quickstart\n\nThe following shows the code that you'll run in the `google/cloud/retail/quickstart/` directory, which should give you a taste of the Retail API C++ client library API. \n\n #include \"google/cloud/retail/v2/catalog_client.h\"\n #include \u003ciostream\u003e\n\n int main(int argc, char* argv[]) try {\n if (argc != 2) {\n std::cerr \u003c\u003c \"Usage: \" \u003c\u003c argv[0] \u003c\u003c \" project-id\\n\";\n return 1;\n }\n\n namespace retail = ::google::cloud::retail_v2;\n auto client =\n retail::CatalogServiceClient(retail::MakeCatalogServiceConnection());\n\n // The service only accepts \"global\" as the location for ListCatalogs()\n auto const location =\n \"projects/\" + std::string(argv[1]) + \"/locations/global\";\n for (auto r : client.ListCatalogs(location)) {\n if (!r) throw std::move(r).status();\n std::cout \u003c\u003c r-\u003eDebugString() \u003c\u003c \"\\n\";\n }\n\n return 0;\n } catch (google::cloud::Status const& status) {\n std::cerr \u003c\u003c \"google::cloud::Status thrown: \" \u003c\u003c status \u003c\u003c \"\\n\";\n return 1;\n }\n\n### Main classes\n\nThis library offers multiple `*Client` classes, which are listed below. Each one of these classes exposes all the RPCs for a gRPC `service` as member functions of the class. This library groups multiple gRPC services because they are part of the same product or are often used together. A typical example may be the administrative and data plane operations for a single product.\n\nThe library also has other classes that provide helpers, configuration parameters, and infrastructure to mock the `*Client` classes when testing your application.\n\n- [`retail_v2::CatalogServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1CatalogServiceClient)\n- [`retail_v2::CompletionServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1CompletionServiceClient)\n- [`retail_v2::PredictionServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1PredictionServiceClient)\n- [`retail_v2::ProductServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1ProductServiceClient)\n- [`retail_v2::SearchServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1SearchServiceClient)\n- [`retail_v2::UserEventServiceClient`](/cpp/docs/reference/retail/2.12.0/classgoogle_1_1cloud_1_1retail__v2_1_1UserEventServiceClient)\n\n### Retry, Backoff, and Idempotency Policies.\n\nThe library automatically retries requests that fail with transient errors, and uses [exponential backoff](https://en.wikipedia.org/wiki/Exponential_backoff) to backoff between retries. Application developers can override the default policies.\n\n### More Information\n\n- [Error Handling](https://cloud.google.com/cpp/docs/reference/common/latest/common-error-handling.html) - describes how the library reports errors.\n- [How to Override the Default Endpoint](/cpp/docs/reference/retail/2.12.0/retail-override-endpoint) - describes how to override the default endpoint.\n- [How to Override the Authentication Credentials](/cpp/docs/reference/retail/2.12.0/retail-override-authentication) - describes how to change the authentication credentials used by the library.\n- [Environment Variables](/cpp/docs/reference/retail/2.12.0/retail-env) - describes environment variables that can configure the behavior of the library."]]