An idiomatic C++ client library for theCloud Speech-to-Text API, a service which converts audio to text by applying powerful neural network models.
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/speech/quickstart/directory, which should give you a taste of the Cloud Speech-to-Text API C++ client library API.
#include "google/cloud/speech/v2/speech_client.h"
#include "google/cloud/project.h"
#include <iostream>
// Configure a simple recognizer for en-US.
void ConfigureRecognizer(google::cloud::speech::v2::RecognizeRequest& request) {
*request.mutable_config()->add_language_codes() = "en-US";
request.mutable_config()->set_model("short");
*request.mutable_config()->mutable_auto_decoding_config() = {};
}
int main(int argc, char* argv[]) try {
auto constexpr kDefaultUri = "gs://cloud-samples-data/speech/hello.wav";
if (argc != 3 && argc != 4) {
std::cerr << "Usage: " << argv[0] << " project <region>|global [gcs-uri]\n"
<< " Specify the region desired or \"global\"\n"
<< " The gcs-uri must be in gs://... format. It defaults to "
<< kDefaultUri << "\n";
return 1;
}
std::string const project = argv[1];
std::string location = argv[2];
auto const uri = std::string{argc == 4 ? argv[3] : kDefaultUri};
namespace speech = ::google::cloud::speech_v2;
std::shared_ptr<speech::SpeechConnection> connection;
google::cloud::speech::v2::RecognizeRequest request;
ConfigureRecognizer(request);
request.set_uri(uri);
request.set_recognizer("projects/" + project + "/locations/" + location +
"/recognizers/_");
if (location == "global") {
// An empty location string indicates that the global endpoint of the
// service should be used.
location = "";
}
auto client = speech::SpeechClient(speech::MakeSpeechConnection(location));
auto response = client.Recognize(request);
if (!response) throw std::move(response).status();
std::cout << response->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 service as member functions of the class. This library groups multiple 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.
[[["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 Cloud Speech-to-Text API C++ client library, which enables conversion of audio to text using neural network models.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate is version 2.37.0-rc, with numerous previous versions available for reference, down to version 2.11.0, all accessible via links.\u003c/p\u003e\n"],["\u003cp\u003eThe library includes several \u003ccode\u003e*Client\u003c/code\u003e classes, such as \u003ccode\u003eAdaptationClient\u003c/code\u003e and \u003ccode\u003eSpeechClient\u003c/code\u003e for both v1 and v2, each offering RPC functions for their respective services.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Cloud C++ client libraries, including this one, do not adhere to Semantic Versioning, even though they are generally available (GA).\u003c/p\u003e\n"],["\u003cp\u003eThe document includes quickstart code examples demonstrating how to use the library for speech recognition, along with details on error handling, endpoint overrides, authentication credentials, retry policies, and relevant environment variables.\u003c/p\u003e\n"]]],[],null,["Version 2.35.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/speech/latest)\n- [2.41.0](/cpp/docs/reference/speech/2.41.0)\n- [2.40.0](/cpp/docs/reference/speech/2.40.0)\n- [2.39.0](/cpp/docs/reference/speech/2.39.0)\n- [2.38.0](/cpp/docs/reference/speech/2.38.0)\n- [2.37.0](/cpp/docs/reference/speech/2.37.0)\n- [2.36.0](/cpp/docs/reference/speech/2.36.0)\n- [2.35.0](/cpp/docs/reference/speech/2.35.0)\n- [2.34.0](/cpp/docs/reference/speech/2.34.0)\n- [2.33.0](/cpp/docs/reference/speech/2.33.0)\n- [2.32.0](/cpp/docs/reference/speech/2.32.0)\n- [2.31.0](/cpp/docs/reference/speech/2.31.0)\n- [2.30.0](/cpp/docs/reference/speech/2.30.0)\n- [2.29.0](/cpp/docs/reference/speech/2.29.0)\n- [2.28.0](/cpp/docs/reference/speech/2.28.0)\n- [2.27.0](/cpp/docs/reference/speech/2.27.0)\n- [2.26.0](/cpp/docs/reference/speech/2.26.0)\n- [2.25.1](/cpp/docs/reference/speech/2.25.1)\n- [2.24.0](/cpp/docs/reference/speech/2.24.0)\n- [2.23.0](/cpp/docs/reference/speech/2.23.0)\n- [2.22.1](/cpp/docs/reference/speech/2.22.1)\n- [2.21.0](/cpp/docs/reference/speech/2.21.0)\n- [2.20.0](/cpp/docs/reference/speech/2.20.0)\n- [2.19.0](/cpp/docs/reference/speech/2.19.0)\n- [2.18.0](/cpp/docs/reference/speech/2.18.0)\n- [2.17.0](/cpp/docs/reference/speech/2.17.0)\n- [2.16.0](/cpp/docs/reference/speech/2.16.0)\n- [2.15.1](/cpp/docs/reference/speech/2.15.1)\n- [2.14.0](/cpp/docs/reference/speech/2.14.0)\n- [2.13.0](/cpp/docs/reference/speech/2.13.0)\n- [2.12.0](/cpp/docs/reference/speech/2.12.0)\n- [2.11.0](/cpp/docs/reference/speech/2.11.0) \n\nCloud Speech-to-Text API C++ Client Library\n===========================================\n\nAn idiomatic C++ client library for the [Cloud Speech-to-Text API](https://cloud.google.com/speech), a service which converts audio to text by applying powerful neural network models.\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/speech/quickstart/` directory, which should give you a taste of the Cloud Speech-to-Text API C++ client library API. \n\n #include \"google/cloud/speech/v2/speech_client.h\"\n #include \"google/cloud/project.h\"\n #include \u003ciostream\u003e\n\n // Configure a simple recognizer for en-US.\n void ConfigureRecognizer(google::cloud::speech::v2::RecognizeRequest& request) {\n *request.mutable_config()-\u003eadd_language_codes() = \"en-US\";\n request.mutable_config()-\u003eset_model(\"short\");\n *request.mutable_config()-\u003emutable_auto_decoding_config() = {};\n }\n\n int main(int argc, char* argv[]) try {\n auto constexpr kDefaultUri = \"gs://cloud-samples-data/speech/hello.wav\";\n if (argc != 3 && argc != 4) {\n std::cerr \u003c\u003c \"Usage: \" \u003c\u003c argv[0] \u003c\u003c \" project \u003cregion\u003e|global [gcs-uri]\\n\"\n \u003c\u003c \" Specify the region desired or \\\"global\\\"\\n\"\n \u003c\u003c \" The gcs-uri must be in gs://... format. It defaults to \"\n \u003c\u003c kDefaultUri \u003c\u003c \"\\n\";\n return 1;\n }\n std::string const project = argv[1];\n std::string location = argv[2];\n auto const uri = std::string{argc == 4 ? argv[3] : kDefaultUri};\n namespace speech = ::google::cloud::speech_v2;\n\n std::shared_ptr\u003cspeech::SpeechConnection\u003e connection;\n google::cloud::speech::v2::RecognizeRequest request;\n ConfigureRecognizer(request);\n request.set_uri(uri);\n request.set_recognizer(\"projects/\" + project + \"/locations/\" + location +\n \"/recognizers/_\");\n\n if (location == \"global\") {\n // An empty location string indicates that the global endpoint of the\n // service should be used.\n location = \"\";\n }\n\n auto client = speech::SpeechClient(speech::MakeSpeechConnection(location));\n auto response = client.Recognize(request);\n if (!response) throw std::move(response).status();\n std::cout \u003c\u003c response-\u003eDebugString() \u003c\u003c \"\\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 service as member functions of the class. This library groups multiple 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- [`speech_v1::AdaptationClient`](/cpp/docs/reference/speech/2.35.0/classgoogle_1_1cloud_1_1speech__v1_1_1AdaptationClient)\n- [`speech_v1::SpeechClient`](/cpp/docs/reference/speech/2.35.0/classgoogle_1_1cloud_1_1speech__v1_1_1SpeechClient)\n- [`speech_v2::SpeechClient`](/cpp/docs/reference/speech/2.35.0/classgoogle_1_1cloud_1_1speech__v2_1_1SpeechClient)\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/speech/2.35.0/speech-override-endpoint) - describes how to override the default endpoint.\n- [How to Override the Authentication Credentials](/cpp/docs/reference/speech/2.35.0/speech-override-authentication) - describes how to change the authentication credentials used by the library.\n- [Override Retry, Backoff, and Idempotency Policies](/cpp/docs/reference/speech/2.35.0/speech-override-retry) - describes how to change the default retry policies.\n- [Environment Variables](/cpp/docs/reference/speech/2.35.0/speech-env) - describes environment variables that can configure the behavior of the library."]]