Structured Data Markup Validation and Testing Tools

Tools for testing structured data markup and rich snippet display, including microformats and schema.org marked up in microdata, RDFa, RDFa Lite and JSON-LD.

When testing vocabularies and schemas, note that error messages from validators may be related to the usage requirements of only that specific data consumer, especially validation error pertaining to required fields or required properties.

Main Multi-Format Validators

Google Structured Data Testing Tool
Google Webmaster Tools
Google's tool for validating schema.org, microformats and other structured data, and for generating previews of rich snippets in Google search results for supported types. Handles HTML marked up with microdata, RDFa and RDFa Lite.

Structured Data Testing Tool Bookmarklet
AJ Kohn
One-click access to Structured Data Testing Tool information on the page you're viewing.

Yandex Structured Data Testing Tool
Yandex Webmaster
Yandex's tool for validating schema.org, microformats, JSON-LD and other structured data.

Structured Data Linter
structured-data.org
Validation and visualization tool for microdata, JSON-LD and RDFa, along with vocabulary validation support for schema.org, FOAF, SIOC, SKOS and Dublin Core (DCMI).

Sindice Web Data Inspector
Sindice
Structured data visualization and validation tool for RDF files, HTML pages embedding microformats and XHTML pages embedding RDFa (beta).

Bing also provides a beta Markup Validator, but use of this tool requires you first to login to Bing Webmaster Tools. Note that once logged in a webmaster can use the Validator to check the markup of any URL, not just the URLs of domains belonging to that Webmaster Tools account.

Open Graph Tools

Open Graph Debugger
Facebook Developers
Open Graph Object debugger from Facebook.

RDFa Tools

RDFa Play
rdfa.info
A real-time RDFa 1.1 editor, data visualizer and debugger (beta).

Microdata Tools

Microdata Parser
SEO Moves
HTML5 microdata parser that displays details for each microdata type.

JSON-LD Tools

JSON-LD Playground
json-ld.org
A web-based JSON-LD viewer and debugger (beta).

Google Validators for Specific Item Types

Email Markup Tester
Google Developers/Google Webmaster Tools
Validator for JSON-LD and microdata, providing properties for each entity and specific error messages for invalid input.

Corporate Contacts Markup Tester
Google
Google's tool for validating schema.org/Organization and schema.org/ContactPoint markup, with JSON-LD support.

Event Markup Tester
Google
Google's tool for validating schema.org/Event markup, with JSON-LD support.

Structured Data Conversion Tools and Utilities

RDF Translator
Alex Stolz / Martin Hepp / Bene Rodriguez-Castro
A multi-format conversion tool for structured markup, providing conversions to and from RDFa, microdata, JSON-LD, RDF/XML, RDF/JSON and more. Conversion input can be a URI or text. Comes with a REST API for developers.

Convert RDFa to JSON-LD [Bookmarklet]
Niklas Lindström
Extracts RDFa from the current page and displays it as JSON-LD.

Chrome Plugins/Extensions

Microdata.reveal
J.C. Darwin
"This extension will parse the currently loaded page, and present an icon in the browser address bar when the page contains HTML microdata (green)."

Microdata/JSON-LD sniffer
Matthis de Wit
"This extension lets you know if there is Microdata or JSON-LD on a website an shows it to you."

Semantic Inspector
Yoichiro Tanaka
"This extension shows you a structure written with HTML Microdata."

META SEO Inspector
Omiod
"Useful to inspect the meta data found inside web pages, usually not visible while browsing."

Green Turtle RDFa
Alex Milowski
"An implementation and viewer of RDFa 1.1 (http://www.w3.org/TR/rdfa-core/) triples…"