Organization of Schemas

The schemas are a set of 'types', each associated with a set of properties. The types are arranged in a hierarchy.
The core vocabulary currently consists of 583 Types, 846 Properties, and 114 Enumeration values.

Browse the full hierarchy:
Or you can jump directly to a commonly used type:
See also the releases page for recent updates and project history.

We also have a small set of primitive data types for numbers, text, etc. More details about the data model, etc. are available here.


As has grown, we have developed mechanisms for community extension as a way of adding more detailed descriptive vocabulary that builds on the core.

Hosted extensions are managed and published as part of the project, with their design often led by one of more dedicated community groups.

External extensions live elsewhere in the Web, typically managed by other organizations with their own processes and collaboration mechanisms. Please consult external documentation for full details of their vocabulary, versioning system and release history.

Hosted Extensions

Specialized terms from hosted extensions can be used alongside core terms like Event and Person. For example in the auto extension there is a property for emissionsCO2, and in the bibliographic extension we have a property publisherImprint.

Using the extension mechanism the core vocabulary is extended by the following hosted extensions:

Note: the 'pending' and 'meta' hosted extensions are part of's schema development process.

We use the 'pending' extension as a staging area for new terms that are under discussion and review. Implementors and publishers are cautioned that terms in the pending extension may lack consensus and that terminology and definitions could still change significantly after community and steering group review. Consumers of data who encourage use of such terms are strongly encouraged to update implementations and documentation to track any evolving changes, and to share early implementation feedback with the wider community.

The 'meta' extension is primarily for vocabulary used internally within to support technical definitions and site functionality. These terms are not intended for general usage in the public Web.

Unlike other core and extension terms, these extensions may be updated at any time without the need for a full release.

External Extensions

The steering group does not officially approve external extensions - they are fully independent. We list here some notable extensions that extend in interesting and useful ways.