Public API This assumes you properly have your app setup in the partner's dashboard with the correct keys and redirect URIs.
REST (sync) For REST calls, the shop domain and access token are required.
use Osiset\BasicShopifyAPI\BasicShopifyAPI;
use Osiset\BasicShopifyAPI\Options;
use Osiset\BasicShopifyAPI\Session;
// Create options for the API
$options = new Options();
$options->setVersion('2020-01');
// Create the client and session
$api = new BasicShopifyAPI($options);
$api->setSession(new Session('example.myshopify.com', 'access-token-here'));
// Now run your requests...
$result = $api->rest(...);