The W3C has announced the launch of the Nu Markup Validation Service, "a non-DTD-based markup validator being made available to the community in parallel to the existing DTD-based validator.w3.org W3C markup validator. The W3C Nu Markup Validation Service uses the same backend as the Validator.nu site, which is also the backend for the HTML5-checking feature of validator.w3.org. The Nu Markup Validation Service is a separate, standalone validator which provides that same HTML5-checking feature while also offering a user interface that exposes additional options, such as full validation support for XHTML5 documents, and the ability to validate documents that contain features from RDFa Core 1.1 and from RDFa Lite 1.1."
Ivan Herman commented, "From a Semantic Web point of view it is important to note that the default setting of the validator validates HTML5 with RDFa 1.1. Lite and with microdata, the two simpler syntaxes to add structured data to HTML. Furthermore, the user can also choose the option of validating with RDFa 1.1 (instead of RDFa Lite) as well as microdata."
Image: Courtesy W3C