Developing Feeds with Rss and Atom

B.4. Validators

Online validators can check to ensure your feeds are correctly formed:

http://feedvalidator.org/

The most up-to-date validator, for both Atom and RSS

http://www.ldodds.com/rss_validator/1.0/validator.html

Leigh Dodd's experimental RSS 1.0 validator

http://aggregator.userland.com/validator

Userland Software's RSS validator

http://www.w3.org/RDF/Validator

The W3C's RDF validator