GCloud Auth is a PHP Experts, Inc., Project for authenticating with Google Cloud API without needing the huge gcloud binary.

As of April 2025, the google-cloud-cli weighs in at around 150 MB, not counting dependencies, and over 550 MB counting dependencies, on modern Linux systems.

Using the google/apiclient composer package itself weighs in at 141 MB.

This project, by comparison, weighs in around 10 KB (or 15,000x smaller).

It provides everything you need to retrieve an OAuth2 token for authenticating with Google Cloud API services. It autogenerates the JWT token necessary for this, using ext-openssl.

It includes a drop-in phpexperts/rest-speaker GoogleAuth driver, but it can also be used standalone by any PHP project.

Via Composer

composer require phpexperts/gcloud-auth

For use with phpexperts/rest-speaker:

use PHPExperts\GoogleCloudAuth\GoogleCloudAuth;
use PHPExperts\RESTSpeaker\RESTSpeaker;

$api = new RESTSpeaker(new GoogleCloudAuth('relative/path/to/services.json'));

For use with any other PHP project:

use PHPExperts\GoogleCloudAuth\GoogleCloudAuth;
$gcloudAuth = new GoogleCloudAuth('relative/path/to/services.json');

// Returns the raw Oauth2Token as a string.
$gcloudOauth2Token = $gcloudAuth->obtainGCloudOauthToken();

$url = "https://storage.googleapis.com/storage/v1/b?project=$projectId";
$http = new \GuzzleHttp\Client([
    'headers' => [
        'Content-Type'  => 'application/json',
        'Authorization' => "Bearer $gcloudOauth2Token",
    ]
]);
$response = $http->get($url);

✔ Can authenticate with GCloud ✔ Handles invalid service account path ✔ Handles invalid service account data ✔ Handles error responses from Google Cloud ✔ Can override time for testing ✔ Will cache the OAuth2 Token until expiration ✔ Can synthesize speech using the GCloud API

phpunit --testdox

Theodore R. Smith [email protected]
GPG Fingerprint: 4BF8 2613 1C34 87AC D28F 2AD8 EB24 A91D D612 5690
CEO: PHP Experts, Inc.

MIT license. Please see the license file for more information.