v.php

<?php

use Phalcon\Validation\Validator\PresenceOf;
use Phalcon\Validation\Validator\StringLength;

$validation = new Phalcon\Validation();

$validation->add('name', new PresenceOf([
  'message' => 'The name is required'
]);

$validation->add('name', new StringLength([
  'min' => 5,
  'messageMinimum' => 'The name is too short',
  'max' => 10,
  'messageMaximum' => 'The name is too long',
]);

$validation->add('created', new Regex([
  'format' => '/[0-9]{4}\-[0-9]{2}\-[0-9]{2}/',
  'message' => 'The date is not valid'
]);

$messages = $validation->validate($_POST);
if (count($messages) {
  foreach ($messages as $message) {
    echo $message, PHP_EOL; 
  }
}