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LTeX LS Plus (LanguageTool)

LTeX LS Plus is a grammar and spelling checker for LaTeX, Markdown, BibTeX, and other prose-heavy formats. It is based on LanguageTool and works well for academic writing.

TeXlyre connects to LTeX LS Plus via WebSocket using lsp-ws-proxy.

1. Install the server​

Download and extract LTeX LS Plus from the releases page.

Example for Linux x64:

VERSION="18.7.0-alpha.nightly.2026-04-25"
ARCHIVE="ltex-ls-plus-${VERSION}-linux-x64.tar.gz"

curl -L -o "$ARCHIVE" \
  "https://github.com/ltex-plus/ltex-ls-plus/releases/download/nightly/$ARCHIVE"

tar -xzf "$ARCHIVE"

This creates a directory such as:

ltex-ls-plus-18.7.0-alpha.nightly.2026-04-25

LTeX LS Plus requires Java. If Java is not already installed, install a recent JRE, such as Temurin JRE 21.

2. Install the WebSocket proxy​

TeXlyre requires a WebSocket transport. lsp-ws-proxy bridges WebSocket to stdio.

Install lsp-ws-proxy:

cargo install lsp-ws-proxy --locked

3. Run the server​

Start the proxy and launch LTeX LS Plus over stdio:

lsp-ws-proxy -l 127.0.0.1:7020 -- ./ltex-ls-plus-18.7.0-alpha.nightly.2026-04-25/bin/ltex-ls-plus

If you use a manually downloaded JRE, set JAVA_HOME first:

export JAVA_HOME="/path/to/jre"
lsp-ws-proxy -l 127.0.0.1:7020 -- ./ltex-ls-plus-18.7.0-alpha.nightly.2026-04-25/bin/ltex-ls-plus
  • The proxy listens on ws://localhost:7020
  • Keep this process running while using TeXlyre

4. TeXlyre configuration​

You can use more than one LSP at the same time. To do this, simply add another config block below in the same list.

Keep everything inside the square brackets [ ] and separate each { } block with a comma.

Paste the following JSON into Settings ⚙️ → LSP → Generic LSP → LSP Configurations.

[
  {
    "id": "ltex-ls",
    "name": "LTeX LS Plus",
    "enabled": true,
    "fileExtensions": ["tex", "latex", "typ", "typst", "bib", "md", "markdown"],
    "languageIdMap": {
      "tex": "latex",
      "latex": "latex",
      "typ": "typst",
      "typst": "typst",
      "bib": "bibtex",
      "md": "markdown",
      "markdown": "markdown"
    },
    "transportConfig": {
      "type": "websocket",
      "url": "ws://localhost:7020",
      "contentLength": false
    },
    "clientConfig": "{\"rootUri\":\"file:///\",\"workspaceFolders\":[],\"capabilities\":{\"workspace\":{\"configuration\":true},\"window\":{\"workDoneProgress\":false}},\"initializationOptions\":{\"ltex\":{\"language\":\"en-US\",\"additionalRules\":{\"motherTongue\":\"\"},\"dictionary\":{},\"disabledRules\":{},\"enabledRules\":{}}}}"
  }
]

Debugging​

To check that the server starts correctly, run it directly first:

./ltex-ls-plus-18.7.0-alpha.nightly.2026-04-25/bin/ltex-ls-plus

To confirm the WebSocket proxy is listening:

lsp-ws-proxy -l 127.0.0.1:7020 -- ./ltex-ls-plus-18.7.0-alpha.nightly.2026-04-25/bin/ltex-ls-plus

Common things to check:

  • Make sure the path to ltex-ls-plus is correct.
  • Make sure Java is installed and available on PATH, or set JAVA_HOME.
  • If you change the proxy port, update transportConfig.url.
  • If diagnostics do not appear, restart both the proxy and TeXlyre.