peggyjs/peggy

Health v2 · maintenance only

Adoption not part of the score

1176 stars · 78 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Peggy is a parser generator for JavaScript based on parsing expression grammars (PEG), producing fast parsers with excellent error reporting. It is the actively maintained successor to PEG.js and can be used from the command line, browser, or JavaScript API.

Use cases

• generate a parser from a PEG grammar in JavaScript
• build a DSL interpreter or compiler in Node.js
• parse custom config or data file formats
• migrate a project from PEG.js to a maintained parser generator
• pre-generate a parser at build time with no runtime dependency
• experiment with grammars in an online editor

When to choose

• you need a parser for a custom language or data format in JavaScript/TypeScript
• you want strong error reporting out of the box
• you want a PEG.js-compatible, actively maintained tool
• you prefer pre-generating parsers at build time for speed

When to avoid

• you need parser combinators or a runtime parser library style rather than code generation
• you need LR/LALR-style ambiguity handling rather than PEG semantics
• you are not working in a JavaScript runtime

Facets

library · maturity active

parser compiler cli developer-tools parsers programming-languages developer-tools web-development browser cli cross-platform peg parser-generator grammar pegjs-successor typescript-types source-maps nodejs

Member repositories

For agents

markdown · JSON · MCP: product_card(name="peggyjs/peggy")