Toon Format

Token-Oriented Object Notation (TOON)

Skill by ara.so — Daily 2026 Skills collection.

TOON is a compact, human-readable encoding of the JSON data model that minimizes tokens for LLM input. It combines YAML-style indentation for nested objects with CSV-style tabular layout for uniform arrays, achieving ~40% token reduction while maintaining or improving LLM comprehension accuracy.

Installation

# npm
npm install @toon-format/toon

# pnpm
pnpm add @toon-format/toon

# yarn
yarn add @toon-format/toon

CLI

# Install globally
npm install -g @toon-format/toon

# Convert JSON file to TOON
toon encode input.json
toon encode input.json -o output.toon

# Convert TOON back to JSON
toon decode input.toon
toon decode input.toon -o output.json

# Pipe support
cat data.json | toon encode
cat data.toon | toon decode

# Pretty-print JSON output
toon decode input.toon --pretty

# Show token count comparison
toon encode input.json --stats

Core API

encode / stringify

import { encode, decode } from '@toon-format/toon';