OntoUML Schema v1.0.0 🎉

The first stable release of the OntoUML Schema — a JSON Schema representation of ontologies based on the OntoUML Metamodel. It defines the canonical JSON serialization of OntoUML models, enabling their validation and exchange over HTTP.

After a series of 1.0.0-draft previews, the schema and its serialization format are now considered stable.

Highlights

• 📦 Published on npm — install with npm install ontouml-schema and validate models with any JSON Schema validator (e.g. Ajv).
• 🧩 Full OntoUML Metamodel coverage — projects, model elements, diagrams, views, and shapes, including class/relation/property stereotypes, ontological natures, and aggregation kinds.
• ✅ JSON Schema 2020-12 — migrated to the latest JSON Schema specification.
• 🌐 Resolvable URI — the schema is available at https://w3id.org/ontouml/schema/v1.0.0.
• 📚 Documentation website — a full Docusaurus site documenting every definition, enumeration, and metadata structure.

Notable changes since the drafts

• Renamed Link to Anchor and added Package to PackageableElement (#31).
• The elements array now includes Property.
• Language-tagged text is now modeled as objects; modified timestamps are optional.
• Added metamodel serialization examples.

Installation

npm install ontouml-schema

Use

const schema = require('ontouml-schema');
const Ajv = require('ajv');
const validate = new Ajv().compile(schema);

validate({ type: 'Project', id: 'p1', name: { en: 'My Ontology' } });

Maintainers

Developed by the Semantics, Cybersecurity & Services (SCS) Group, University of Twente.

Full Changelog: https://github.com/OntoUML/ontouml-schema/commits/v1.0.0