Parser infrastructure for the TypeScript stack. Apache 2.0. Independently funded, sustainable through OSS-aligned commercial services.

• pegmill — PEG parser generator with parametric rules. Drop-in for PEG.js 0.10.0. Ships on npm: npm install pegmill (latest: v0.1.3 with TypeScript declarations and esbuild browser bundle).
• pegmill.github.io — landing with roadmap and comparison against Outlines, XGrammar, and llama.cpp GBNF.

Constrained decoding for open-weight LLMs lives in Python (Outlines) or C++ (llama.cpp GBNF; XGrammar ships C++ with JS via emscripten build, no npm package). TypeScript has no equivalent with full PEG expressiveness. Pegmill fills that gap.

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