app/Rules/OneEmailPerLine.php
use Illuminate\Contracts\Validation\Rule; class OneEmailPerLine implements Rule{ public function passes($attribute, $value) { if ($value === null || empty(trim($value))) return true; foreach (preg_split("/\r\n|\n|\r/", $value) as $email) { $email = trim($email); if (!filter_var($email, FILTER_VALIDATE_EMAIL)) { return false; } } return true; } public function message() { return 'You need one valid email per line.'; }}