<?php

$v = new Filtr\Validator();
$v->required('email')->isNotBlank()->isEmailAddress();
$v->required('password')->isNotBlank()->isHavingLength(8, 32);
$v->key('remember_me')->isTrue();

$result = $v->validate([
    'email' => '[email protected]',
    'password' => 'not-much-secret',
]);

if ($result->valid()) {
    // ... proceed
} else {
    echo implode('<br>', $result->errors());
}