• Public
  • Public/Protected
  • All


Discord npm Build Status Coverage Status Dependency status styled with prettier

Sauce Test Status



Chevrotain is a very 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.



  1. Parsing DSL.

  2. Lexer Engine

  3. High Performance.

  4. Railroad Diagrams Generation.

  5. Grammar Reflection/Introspection.

    • The Grammar's structure is known and exposed at runtime.
    • Can be used to implement advanced features such as dynamically generated syntax diagrams or Syntactic error recovery.
  6. Well tested with ~100% code coverage, Unit & Integration tests


  • 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
    • Explicit version number:
      • https://unpkg.com/chevrotain@2.0.0/lib/chevrotain.js
      • https://unpkg.com/chevrotain@2.0.0/lib/chevrotain.min.js

Documentation & Resources




Chevrotain should run on any modern JavaScript ES5.1 runtime.

  • The CI build runs the tests under:

    • Node.js (6 / 8 / 9).
    • Latest stable: Chrome, FireFox, Safari, IE Edge and IE 11.
  • 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:

Generated using TypeDoc