RDFa
RDFa Play
A real-time RDFa 1.1 editor, data visualizer and debugger.
The Ruby RDFa Distiller
The Ruby RDFa distiller can take any RDF format, including RDFa, and output it in a variety of other RDF formats.
The Python RDFa Distiller
The Python RDFa distiller can take an HTML document containing RDFa and output it in a variety of RDF formats. The Python package can be downloaded and used from any Python application; it relies on the RDFLib package.
W3C’s Nu Markup Validation Service
The tool validates, as a default option, RDFa 1.1 Lite in HTML5; using the “Preset” in the “Options” the validator can also be instructed to validate RDFa 1.1 Core with (X)HTML5. (The validator also checks Microdata markup.)
The Structured Data Linter
The structured data linter can be used to check not only RDFa markup, but Microdata markup as well.