Parser Building Toolkit for JavaScript

finite state machine tokenizer

High-performance CSS parser optimized for static analysis and formatting

Reduce LLM token costs by 30-60% with TONL format. TypeScript library & CLI for bidirectional JSON/YAML ↔ TONL conversion with real GPT-5 tokenizer.

ZON → 35-70% cheaper LLM prompts than JSON/TOON. Zero overhead.

quick js checker to keep your builds right!

AI Model Tokenization with Realtime Token Counting Built with Next.js

Web tool to count LLM tokens (GPT, Claude, Llama, ...)

A faster than tiktoken tokenizer with first-class support for Vercel's AI SDK.

A lossless JSON/JSON5 tokenizer and parser for Node.js that maintains indentation, spacing, and comments.

Interface interativa para simulação de pré-vendas de tokens e criação de lançamentos fictícios em tempo real.

📐 Fast token estimation at 94% accuracy of a full tokenizer in a 2kB bundle

Lightweight JSON tokenizer with symmetric dictionary encoding for compression and optimization

Promise based streaming tokenizer

The fastest JavaScript BPE Tokenizer Encoder Decoder for OpenAI's GPT models (gpt-5, gpt-o*, gpt-4o, etc.). Port of OpenAI's tiktoken with additional features.

🪁 Parser grammar builder. Write parsers with pattern matching.

Lexer / tokenizer

a lightweight TypeScript/Javascript library for progressively parsing streamed text (LLM/SSE-like) into structured events. Perfect for LLM powered stream-chat applications

An advanced tokenizer made with typescript

Parse any kind of broken json for scrapping easily