---
id: lark
version: "1.3.1"
license: MIT
license_treatment: permissive
maintenance: active
---

# lark — a modern parsing library

License: permissive · Maintenance: active · Popularity: top 1,000 on PyPI

## Install

pip install lark
uv add lark
poetry add lark

## Description

Lark is a modern general-purpose parsing library for Python.
With Lark, you can parse any context-free grammar, efficiently, with very little code.
Main Features:
- Builds a parse-tree (AST) automagically, based on the structure of the grammar
- Earley parser
- Can parse all context-free grammars
- Full support for ambiguous grammars
- LALR(1) parser
- Fast and light, competitive with PLY
- Can generate a stand-alone parser
- CYK parser, for highly ambiguous grammars
- EBNF grammar
- Unicode fully supported
- Automatic line & column tracking
- Standard library of terminals (strings, numbers, names, etc.)
- Import grammars from Nearley.js
- Extensive test suite
- And much more!
Since version 1.2, only Python versions 3.8 and up are supported.

## AI interpretation — verify before relying

Lark is a parsing library that builds abstract syntax trees from context-free grammars using Earley, LALR(1), or CYK parsers, supporting ambiguous grammars and EBNF syntax with full Unicode support.

Verdict: Lark is a production-ready, actively maintained parsing library with no dependencies, permissive licensing, and zero known vulnerabilities. It is well-suited for projects requiring flexible grammar-based parsing with minimal installation overhead.

[View on SkillFed](https://skillfed.io/packages/lark) · [View on PyPI](https://pypi.org/project/lark/)