Rob Allen has written up a brief tutorial showing you how to use the Zend/Filter component independently from a Zend Framework application. In his example he integrates it into a simple API endpoint.
Any data that you receive needs to be checked and validated. There are number of ways to do this including PHP's filter_var, but I prefer Zend-InputFilter. This is how to use it as a stand-alone component.
He shows you how to get the component installed (along with the Zend ServiceManager) and the creation of a basic validation/filtering on "author" data. He explains the different parts that make up the instance: required, filters and validators. He then shows how to use it in your request and the resulting output if something fails.