RDF Studio

Browse, edit, and visualize RDF knowledge graphs directly in VS Code. Load Turtle (.ttl) files into an in-memory SPARQL store, connect to remote SPARQL endpoints, and explore ontologies, entities, and their relationships with a visual editor.

Built on Oxigraph WASM for full SPARQL 1.1 support — no external triplestore needed.

Features

Knowledge Graph Browser

• Namespace-grouped tree with type-colored icons showing classes, instances, and instance counts
• Source grouping — local files and remote SPARQL endpoints displayed separately in the tree
• Schema view for OWL classes showing declared and inherited properties with domain/range
• Full superclass chain — breadcrumb pills showing the complete class hierarchy (e.g. Fine Squad > Squad > Organization), each clickable to navigate

Detail View

• Instance detail with Source, Relation, and Target columns
• Parameters (literal values), Outgoing and Incoming relationship sections
• Type-colored entity boxes — consistent HSL hue per type across tree, detail view, and graph
• Inherited properties — when a local class extends a remote class (via rdfs:subClassOf), remote properties are auto-fetched and displayed read-only with source attribution. Local data renders instantly; remote data loads in the background
• Inline editing — click a value to edit, Enter to save, Esc to cancel
• Add parameter and Add relationship buttons with form dialogs
• Edit parameter — hover to reveal pencil icon on any value

Full CRUD

• Create ontologies, classes, properties, and instances via modal forms
• Edit labels, comments, parameters, and relationships via inline or form editing
• Delete with toast notification and Undo support
• File-safe compacting — writes only use prefixes declared in the target TTL file, preventing undeclared prefix errors
• Auto-prefix injection — cross-ontology references automatically add missing @prefix declarations

Remote SPARQL Endpoints

• Connect to any SPARQL 1.1 endpoint (Apache Jena Fuseki, Virtuoso, GraphDB, Stardog, etc.)
• Auto-discover named graphs for endpoints that use named graph patterns
• Lazy loading with 5-minute TTL cache for remote instances (up to 15,000 per class)
• Remote search with multiple strategies — exact match, IRI construction, and text search
• Cross-graph inheritance — local instances automatically show properties from their remote superclass, bridging local and remote knowledge

SPARQL & Graph Visualization

• SPARQL query panel with preset queries and clickable result tables
• Neighborhood graph — force-directed canvas visualization of an entity's direct connections
• Type-consistent colors — graph nodes use the same color scheme as the tree and detail views
• Click to navigate, right-click to go to source, drag to pan, scroll to zoom

Turtle Language Support

• Hover — label, types, and comment on prefixed names
• Go to Definition (F12) — jump to where an entity is defined
• Autocomplete — type : after a prefix for resource/property completions
• Document Outline (Cmd+Shift+O) — all subjects in a file
• Diagnostics — undefined prefixes and dangling references

Theme Support

• Full light and dark theme support via VS Code CSS variables
• Type-color system with curated hue overrides and automatic lightness band switching

Getting Started

Install from VSIX

Download the latest .vsix from Releases, then:

code --install-extension rdf-studio-1.0.0.vsix

Build from source

git clone https://github.com/stefanavesand/rdf-studio.git
cd rdf-studio
npm install
npm run compile
npx vsce package
code --install-extension rdf-studio-1.0.0.vsix

Reload VS Code. The extension activates automatically when your workspace contains .ttl files.

Try the example

Open the examples/ folder to load the included Solar System knowledge graph — 8 classes, 60+ instances covering stars, planets, moons, spacecraft, and space missions.

How It Works

On activation, the extension loads all .ttl files in the workspace into an in-memory Oxigraph store. All queries (tree views, detail panels, SPARQL) run as SPARQL against this store. Edits are written back to the TTL source files via VS Code's WorkspaceEdit API, supporting undo/redo and source control integration.

Remote SPARQL endpoints can be connected via the globe icon in the tree view header. The remote ontology is loaded on connect; remote instances are fetched on demand with caching. When a local class is a subclass of a remote class, the detail view automatically fetches inherited properties from the remote endpoint.

Roadmap

• SHACL validation — constraint checking against SHACL shapes (schema service exists but is not yet wired to the UI)
• Rename refactoring — rename entities across all files
• RDF/XML and JSON-LD — additional serialization formats

Development

npm install
npm run watch    # recompile on change

Press F5 in VS Code to launch an Extension Development Host.

npm test         # run mocha tests
npm run compile  # one-shot compile
npx vsce package # build .vsix

License

MIT — see LICENSE.