Laravel - Validation - A Note On Optional Fields

By default, Laravel includes the TrimStrings and ConvertEmptyStringsToNull middleware in your application's global middleware stack. These middleware are listed in the stack by the App\Http\Kernel class. Because of this, you will often need to mark your "optional" request fields as nullable if you do not want the validator to consider null values as invalid. For example:

        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
        'publish_at' => 'nullable|date',

In this example, we are specifying that the publish_at field may be either null or a valid date representation. If the nullable modifier is not added to the rule definition, the validator would consider null an invalid date.