What is gii in Yii 2 and for what it is used ?

Gii is module powerful module provided by Yii framework. It helps you create and generate fully customized forms, models, CRUD for database and more.You can enable Gii by configuring it in the modules property of the application. Depending upon how you created your application, you may find the following code is already provided in the config/web.php configuration file:

$config = [ ... ];

if (YII_ENV_DEV) {
    $config['bootstrap'][] = 'gii';
    $config['modules']['gii'] = [
        'class' => 'yii\gii\Module',
    ];
}