The unstoppable growth of security flaws makes the developers more patient in integrating different security defenses in the application development! Most of the security breaches are due to uninformed or unqualified developers! The good part is that Internet provides a large amount of rules/documentations/guidelines/tools free for use to help the developers in their work! But as the coin has two sides each web application needs to provide two parts of security flaws protection. The first level of defense is the well known protection from the outside world, called user input validation! And the second side is to ensure that the application works without a problem! Which means to protect it from inside out by integrating what is called code contracts! Even thought those two types of protection have similar purposes there is a difference which we are going to present in the research!