SWLS (Semantic Web Language Server) is a VS Code extension that gives you full IDE support when working with Semantic Web formats. Whether you are building ontologies in Turtle, querying graphs with SPARQL, or describing linked data in JSON-LD, SWLS provides the editor features you rely on in other languages: instant diagnostics, smart autocompletion, hover documentation, formatting, and semantic highlighting — all powered by a native language server with a WASM fallback so it works everywhere VS Code runs.Documentation Index
Fetch the complete documentation index at: https://mintlify.com/SemanticWebLanguageServer/swls-vscode/llms.txt
Use this file to discover all available pages before exploring further.
Installation
Install from the VS Code Marketplace or Open VSX Registry in seconds.
Quickstart
Open a Turtle file and see SWLS in action within minutes.
Configuration
Tune every aspect of the language server with the
swls.* settings.Features
Explore diagnostics, completion, hover, rename, formatting, and more.
What SWLS supports
SWLS activates automatically for these file types:| Language | Extensions | Enabled by default |
|---|---|---|
| Turtle | .ttl | ✅ |
| TriG | .trig | ✅ |
| JSON-LD | .jsonld, .json | ✅ |
| SPARQL | .sq, .rq | ⚠️ Experimental |
Get up and running
Install the extension
Search for Semantic Web LSP in the VS Code Extensions panel, or install directly from the Visual Studio Marketplace.
Open a Turtle file
Open any
.ttl file. SWLS activates automatically and starts the language server — no extra configuration needed.See completions and diagnostics
Start typing a prefix like
foaf: to see class and property completions. Syntax errors and undefined prefixes are underlined in real time.Key features
Diagnostics
Syntax errors, undefined prefixes, and SHACL shape violations surfaced inline as you type.
Smart Completion
Context-aware suggestions for prefixes, properties, and classes with domain-based ordering.
Hover & Rename
Hover any IRI for labels and descriptions. Rename local terms across the file.
Semantic Highlighting
Full semantic token highlighting for all four supported languages.
SWLS works entirely offline after installation. It bundles a WASM build of the language server so it runs in VS Code for the Web and in remote/container environments without any additional dependencies.