GraphQL API

OWLGraph automatically generates a GraphQL schema from your loaded ontology. The endpoint is available at /graphql.

Schema Generation

When an ontology is loaded, OWLGraph generates a GraphQL schema:

OWL Construct	GraphQL Equivalent
Class with subclasses	Interface
Leaf class	Type
`rdfs:subClassOf`	`implements`
Object property	Relationship field
Data property	Scalar field
`owl:inverseOf`	`@hasInverse` directive
`owl:FunctionalProperty`	Singular field (not array)

Queries

# Get all dogs
query {
  queryDog {
    name
    hasOwner { name }
  }
}

# Get all animals (subsumption — returns Dogs, Cats, etc.)
query {
  queryAnimal {
    name
    __typename
  }
}

# Filter
query {
  queryBook(filter: { title: { anyofterms: "Dune" } }) {
    title
    writtenBy { name }
  }
}

Mutations

mutation {
  addDog(input: [{
    name: "Rex"
    hasOwner: { name: "Alice" }
  }]) {
    dog {
      name
      hasOwner { name }
    }
  }
}

Write-time materialization still applies — Rex gets ancestor types, and inverse edges are created.

Endpoint

POST https://YOUR-INSTANCE/graphql
Content-Type: application/json

{
  "query": "{ queryDog { name } }",
  "variables": {}
}

Exploring the Schema

Point any GraphQL IDE (GraphiQL, Apollo Studio, Altair) at your instance’s /graphql endpoint. The schema is fully introspectable.

Limitations

Complex class expressions are simplified to named class components
Property chain axioms are enforced by the materializer but not directly visible in the GraphQL schema
The GraphQL schema is regenerated when the ontology is reloaded