Integrity is an web developer’s test tool for MacOSX. Freeware at its finest, a web developer will feed Integrity a URL and the application will then parse through all of the internal and external links and make sure everything is in order.
Greatest thing about this is that it shows a list of the error codes given by the browser and you can filter through it by hiding the good codes. This helps make sure that a website is developed without broken links. Always a plus.