A validator for syndicated feeds is available at the website www.feedvalidator.org. It works with RSS 0.90, 0.91, 0.92, 0.93, 0.94, 1.0, 1.1, and 2.0. It also validates Atom feeds.The validator was conceived and designed by Mark Pilgrim, who also wrote most of the test cases and designed the web front end. Much of the actual back end coding was done by Sam Ruby.