Qlue-UI

Qlue-UI is a modern WebUI for SPARQL, driven by Qlue-ls. It does not target a single, but many SPARQL engines.
It’s small, shiny, and ready to help you explore your RDF data effortlessly.

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Features

SPARQL Editor

• Modern, lightweight WebUI for SPARQL with many language capabilities
  • completion
  • formatting
  • diagnostics
  • code actions
  • hover

Results Renderer

• Result views for ANY sparql operation (including update for QLever endpoints)

Query Execution Tree View

• Live query execution monitoring for QLever backends

Parse Tree View

• Parse tree view for inspecting the internal representation of a SPARQL query

Completion Query Template Editor

• Live completion template editor for rapid iteration on query templates (experimental)

Powerful Formatter with many options

Miscellaneous

• Tabs for multiple queries
• Share queries with your peers
• Proper indentation support for SPARQL ('.' and ';')
• Automatic line break after '.' or ';'
• Automatic addition or removal of PREFIX declarations (configurable)
• Jump to relevant positions in the query
• Manage example queries per SPARQL endpoint
• Easy deployment with Docker
• Clean separation of API and frontend

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Quick Start

Follow these steps to get Qlue-UI up and running:

1. Build and run with Docker

docker compose build
docker compose up

Qlue-UI is now available under http://localhost:7000

2. Configuration

Endpoint configurations are defined in config.default.yaml (copied into the container as config.yaml). To customize, mount your own config.yaml into the container.

3. Environment variables

Variable	Default	Description
CONFIG_FILE	config.yaml	Path to the endpoint configuration file
EXAMPLES_DIR	examples	Directory containing example queries
DB_FILE	data.db	Path to the SQLite database (shared queries)
API_KEY	(unset)	If set, protects write endpoints (PATCH, PUT, POST, DELETE)
CORS_ORIGINS	*	Comma-separated list of allowed CORS origins

4. Deploying with a Proxy

The app runs behind uvicorn with --proxy-headers enabled, so it trusts X-Forwarded-* headers by default.

Your reverse proxy MUST set these headers:

• X-Forwarded-Host
• X-Forwarded-Proto

Note: The "Query Execution Tree View" opens a WebSocket directly from the browser to the QLever backend — it does not go through this proxy.

Apache example

Enable the required modules:

a2enmod proxy proxy_http headers

<VirtualHost *:443>
    ServerName qlue.example.com

    ProxyPreserveHost On
    RequestHeader set X-Forwarded-Proto "https"

    ProxyPass        / http://localhost:7000/
    ProxyPassReverse / http://localhost:7000/
</VirtualHost>

Keyboard Shortcuts

Shortcut	Action
?	Open help
Escape	Close any dialog
Ctrl+Enter	Execute/cancel query
Ctrl+F	Format document
Ctrl+,	Open settings
Tab	Jump to next position
Shift+Tab	Jump to previous position

Commands

Open the command prompt with : (editor must be out of focus) and type a command:

Command	Action
parseTree	Open the parse tree panel
templates	Open the completion templates editor (experimental)
updateExample	Update the current example query
createExample "<name>"	Save the editor content as a new example for the active backend

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Development Setup

For local development, set up the frontend and backend separately.

Backend Setup

The backend uses uv as the package manager.

cd backend
uv sync                                                      # Install dependencies
uv run fastapi dev src/api/main.py                           # Start server on port 8000

Frontend Setup

cd frontend
npm install
npm run dev   # Start dev server on port 5173

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License

Apache License 2.0