Semantic Web Language Server

IDE support for Semantic Web languages — Turtle, TriG, JSON-LD, and SPARQL. Autocompletion, diagnostics, formatting, SHACL validation, and more.

Table of Contents

• Features
• Installation
  • VS Code
  • NeoVim
• Configuration
• Documentation
• Screenshots

Features

Diagnostics

• Syntax errors — immediate feedback on malformed documents
• Undefined prefixes — flags uses of undeclared namespace prefixes
• SHACL shape violations — validates data against loaded SHACL shapes

Completion

• Prefix completion — typing foa expands to foaf: and inserts the prefix declaration
• Property completion — suggests properties ordered by domain relevance
• Class completion — when the predicate is a, suggests applicable classes

Hover

• Shows labels, descriptions, and class information for IRIs

Rename

• Rename terms local to the current file

Formatting

• Format Turtle and JSON-LD documents

Semantic Highlighting

• Full semantic token highlighting for all supported languages

Installation

VS Code

Install from the Visual Studio Marketplace or Open VSX Registry.

On startup the extension looks for a native swls binary — first in its own managed location, then in your PATH. If no binary is found it falls back to a bundled WASM worker so the LSP is available immediately without any extra setup.

In the background it checks GitHub releases for updates. When a newer version is available you will be prompted to install it; after the download completes a window reload switches to the native binary.

NeoVim

A NeoVim plugin is available at SemanticWebLanguageServer/swls.nvim.

Configuration

All settings live under the swls prefix.

Setting	Type	Default	Description
swls.turtle	boolean	true	Enable Turtle language support
swls.jsonld	boolean	true	Enable JSON-LD language support
swls.sparql	boolean	false	Enable SPARQL language support (experimental)
swls.checkUpdate	boolean	true	Check GitHub for new releases on startup
swls.automaticUpdate	boolean	false	Install updates without prompting
swls.log	string	"debug"	Log level: error, warn, info, debug, trace
swls.ontologies	string[]	[]	Extra ontology URLs to load
swls.shapes	string[]	[]	Extra SHACL shape URLs to load
swls.disabled	string[]	[]	Features to disable (e.g. "shapes")
swls.prefixDisabled	string[]	[]	Prefixes from prefix.cc to hide from completions
swls.completion.mode	string	"none"	Property completion mode: none (server default), loose (all properties), strict (domain-matched only)
swls.completion.strict	string[]	[]	Namespace prefixes that require a matching domain even in loose mode
swls.completion.except	string[]	[]	Namespace prefixes always suggested regardless of domain, even in strict mode

Documentation

• lsp-core
• lang-turtle
• lang-jsonld
• lang-sparql
• swls

Screenshots

Undefined prefix	Shape violation

Class completion	Property completion