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Chevrotain is a blazing fast and feature rich Parser Building Toolkit for JavaScript. It can be used to build parsers/compilers/interpreters for various use cases ranging from simple configuration files, to full fledged programing languages.

A more in depth description of Chevrotain can be found in this great article on: Parsing in JavaScript: Tools and Libraries.

It is important to note that Chevrotain is NOT a parser generator. It solves the same kind of problems as a parser generator, just without any code generation. Chevrotain Grammars are pure code which can be created/debugged/edited as any other pure code without requiring any new tools or processes.



  • npm: npm install chevrotain
  • Browser: The npm package contains Chevrotain as concatenated and minified files ready for use in a browser. These can also be accessed directly via UNPKG in a script tag.
    • Latest:
      • https://unpkg.com/chevrotain/lib/chevrotain.js
      • https://unpkg.com/chevrotain/lib/chevrotain.min.js
      • https://unpkg.com/chevrotain/lib_esm/chevrotain.mjs
      • https://unpkg.com/chevrotain/lib_esm/chevrotain.min.mjs
    • Explicit version number:
      • https://unpkg.com/chevrotain@9.1.0/lib/chevrotain.js
      • https://unpkg.com/chevrotain@9.1.0/lib/chevrotain.min.js
      • https://unpkg.com/chevrotain@9.1.0/lib_esm/chevrotain.mjs
      • https://unpkg.com/chevrotain@9.1.0/lib_esm/chevrotain.min.mjs

Documentation & Resources


There is a single dependency (outside this monorepo) to regexp-to-ast library. This dependency is included in the bundled artifacts, for ease of consumption in browsers.


Chevrotain runs on any modern JavaScript ES5.1 runtime. That includes any modern nodejs version, modern browsers and even IE11.

  • Uses UMD to work with common module loaders (browser global / amd / commonjs).


Contributions are greatly appreciated. See CONTRIBUTING.md for details.

Where used

Some interesting samples:

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