XML Nanny 3.0 beta

XML Nanny is a developer tool that provides an Aqua interface for checking XHTML and XML documents for Well-Formedness and Validity either locally or across the network.
XML Nanny is the perfect tool for the Web author who cares!

Checking your XHTML document's validity either locally or remotely is a snap, and XML Nanny's detailed error messages let you know about those embarrassing validation errors so you can debug them immediately.
XML Nanny cares for your XHTML documents in places the W3C web-based validation service can't reach... Suppose you are developing a standards-based Web site or application on your local Web server or behind a firewall. The W3C validator can't reach your document to validate it. XML Nanny can.