> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getcollate.io/llms.txt
> Use this file to discover all available pages before exploring further.

# RDF Indexing

> Understand how Collate uses RDF and Apache Jena Fuseki to power knowledge graph capabilities, semantic search, and SPARQL queries.

# Overview

Collate uses RDF (Resource Description Framework) to build a knowledge graph of your metadata. This enables semantic search, SPARQL (SPARQL Protocol and RDF Query Language) queries, and JSON-LD representations of your data assets.

## What RDF Indexing Enables

RDF indexing extends your metadata catalog with graph capabilities, making it possible to query and explore data relationships beyond simple search.

* **Semantic search** — Query metadata using meaning and relationships, not just keywords.
* **Knowledge graph** — Explore connections between entities across your data catalog.
* **SPARQL queries** — Run graph queries directly against your metadata.
* **JSON-LD serialization** — Export any entity in standard linked data formats (JSON-LD, Turtle, RDF/XML, N-Triples).
* **Ontology support** — Metadata is modeled against the OpenMetadata OWL ontology.

## How It Works

RDF indexing runs as a background application alongside your Collate deployment. Collate uses **Apache Jena Fuseki** as the underlying triple store.

When RDF is enabled:

* New and updated entities are automatically indexed to the triple store.
* Hard-deleted entities are removed from the triple store.
* Existing entities can be reindexed on demand via the RDF Index App.

## Available API Endpoints

Use these endpoints to check RDF status, retrieve entities in linked data formats, or run custom graph queries. Once RDF is enabled, these endpoints are available on your Collate instance:

| Endpoint                                   | Description                                     |
| ------------------------------------------ | ----------------------------------------------- |
| `GET /api/v1/rdf/status`                   | Check whether RDF is enabled                    |
| `GET /api/v1/rdf/entity/{entityType}/{id}` | Get any entity as RDF (JSON-LD by default)      |
| `POST /api/v1/rdf/sparql`                  | Execute a SPARQL query against the triple store |

### Supported RDF Formats

The default format is JSON-LD. Pass `?format=` to the entity endpoint to select a different serialization:

| Format            | Parameter value |
| ----------------- | --------------- |
| JSON-LD (default) | `jsonld`        |
| Turtle            | `turtle`        |
| RDF/XML           | `rdfxml`        |
| N-Triples         | `ntriples`      |