2.1.3 • Public • Published


Langium is a language engineering tool with built-in support for the Language Server Protocol. It has a simple and direct integration with the VS Code extension API.

More information: 🌍

Getting Started

Langium offers a Yeoman generator to create a new language extension for VS Code. The only prerequisite for the following terminal commands is NodeJS version 14 or higher.

  1. Install Yeoman and the Langium extension generator.
npm install -g yo generator-langium
  1. Run the generator and answer a few questions.
yo langium
  1. Open the new folder in VS Code (replace hello-world with the extension name you chose).
code hello-world
  1. Press F5 to launch the extension in a new Extension Development Host window.

  2. Open a folder, create a file with your chosen file name extension (.hello is the default), and see that validation and completion (ctrl+space) works:

Follow the instructions in (in your extension folder) and the documentation on the website to go further.

How Does it Work?

The core of Langium is a grammar declaration language in which you describe multiple aspects of your language:

  • Tokens (keywords and terminal rules)
  • Syntax (parser rules)
  • Abstract syntax tree (AST)

Please follow the Langium documentation to learn how to use this language.

Langium features a command line interface (langium-cli) that reads a grammar declaration and generates TypeScript type declarations for the AST and more.

Integration with the Language Server Protocol (LSP) is done with vscode-languageserver. You have full access to the LSP API in Langium, so you can register additional message handlers or extend the protocol in a breeze.

The main code of Langium consists of a set of services that are connected via dependency injection (DI). You can override the default functionality and add your own service classes by specifying a DI module.


The source repository of Langium includes examples that demonstrate different use cases.

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npm i langium


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