"YOUR_API_KEY"]); $promise = $sparky->request('POST', 'templates/TEMPLATE_ID/preview?draft=true', [ 'substitution_data' => [ 'some_key' => 'some_value', ], ]); try { $response = $promise->wait(); echo $response->getStatusCode()."\n"; print_r($response->getBody())."\n"; } catch (\Exception $e) { echo $e->getCode()."\n"; echo $e->getMessage()."\n"; }