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.
Feed Validator for RSS and Atom
Provides schema-based online validation for Atom and RSS feeds and a large testsuite for developers of similar tools.
Feedvalidator-users Email List
Questions, bugs, patches, and general discussion of FeedValidator.org's Atom and RSS feed processing service.
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.
RSS1.0 Validator (ldodds.com)
An experimental online RSS1.0 Validator
Userland RSS validator
Userland Software's online validator for RSS 0.9x
W3C RDF Validation Service
A full RDF Validation Service - for use with any RDF, not just RSS 1.0
Will the real RSS validator please stand up? [dive into mark]
Elaborates on how the RSS community is in disagreement about the exact format for RSS feeds and individual entries. (June 26, 2003)