Feed Validator for Atom and RSS - This is a validator for syndicated feeds. It works with RSS 0.90, 0.91, 0.92, 0.93, 0.94, 1.0, and 2.0. It also validates Atom feeds. RSS1.0 Validator (ldodds.com) - An experimental online RSS1.0 Validator W3C RDF Validation Service - A full RDF Validation Service - for use with any RDF, not just RSS 1.0 Redland RSS 1.0 Validator and Viewer - Enter the address of an RSS 1.0 feed into the form, and it will be validated and formatted for display. Feedvalidator-users Email List - Questions, bugs, patches, and general discussion of FeedValidator.org's Atom and RSS feed processing service. Userland RSS validator - Userland Software's online validator for RSS 0.9x