Installation

Requirements

  • JetBrains IDE — IntelliJ IDEA 2025.3+ (Ultimate or Community), WebStorm, or other JetBrains IDE with LSP support

  • JDK — 21 or later (bundled with JetBrains IDEs)

  • Node.js — 18 LTS or later, available in PATH (required for the Language Server)

  • @rescript/language-server — 1.0.0 or later (compatible with ReScript 11+); installed per-project or globally

  • ReScript — 11.0 or later, set up in your project (rescript.json present)

Step 1: Install the Plugin

From JetBrains Marketplace

  1. Open your JetBrains IDE

  2. Go to Settings → Plugins → Marketplace

  3. Search for “ReScript”

  4. Click Install

  5. Restart the IDE when prompted

From Disk (Manual)

  1. Download the latest .zip from the GitHub Releases page

  2. Go to Settings → Plugins → ⚙️ → Install Plugin from Disk…

  3. Select the downloaded .zip file

  4. Restart the IDE when prompted

Step 2: Install the ReScript Language Server

The plugin uses the ReScript Language Server for semantic features like code completion, diagnostics, and navigation. The plugin requires @rescript/language-server 1.0.0 or later (compatible with ReScript 11+); the latest stable release is recommended. Install it in your project:

Global Installation

npm install -g @rescript/language-server

yarn global add @rescript/language-server

pnpm add -g @rescript/language-server

Tip

Local installation (per-project) is recommended. The plugin automatically detects the Language Server in your project’s node_modules/ directory.

Automatic Installation

If the Language Server is not found when you open a ReScript project, the plugin displays a notification offering to install it automatically:

  • Install with npm/yarn/pnpm — Installs @rescript/language-server as a dev dependency using the detected package manager. The installation runs in the background, and the Language Server starts automatically when complete.

  • Configure… — Opens the ReScript settings page to set a custom Language Server path.

  • Don’t show again — Dismisses the notification for the current session.

The plugin also shows an editor notification bar at the top of .res files when the Language Server is not detected, with a link to install it.

Detection Order

The plugin searches for the Language Server in this order:

  1. node_modules/.bin/rescript-language-server (project-local)

  2. Parent directories’ node_modules/.bin/ (monorepo support)

  3. node_modules/@rescript/language-server/out/cli.js (fallback)

  4. Global installation (via which / where)

Step 3: Verify

  1. Open a .res file in your project

  2. You should see:

    • Syntax highlighting — Keywords, strings, comments are colored

    • No warning banner — If the Language Server is found, no notification bar appears

    • Code completion — Type a few characters and see completion suggestions

Tip

If the Language Server is not detected, a notification bar will appear at the top of the editor with instructions to install it. Native features (syntax highlighting, code folding, etc.) will still work without the Language Server.

Troubleshooting Installation

See the Troubleshooting page for common installation issues.