A validation engine created for PHP, by Alexandre Gomes Gaigalas ( Copyright (c) 2009-2015). PHP 5.4+ or HHVM 3.3+ are required for using it.
The creators call it "The most awesome validation engine ever created for PHP."
Fluent/Chained builders like:
v::numeric()->positive()->between(1, 256)->validate($myNumber)
Informative, awesome exceptions;
More than 30 fully tested validators.