TOON Converter

TOON (Token-Oriented Object Notation) reduces LLM token usage by 30-60% compared to JSON. Perfect for optimizing prompts and reducing API costs. Learn more

Input

0 tokens (estimated)

Output

0 tokens (estimated)

TOON Syntax Reference

Objects

name: John
age: 30
address:
  city: NYC
  zip: 10001

Primitive Arrays

tags[3]: api,rest,json
numbers[4]: 1,2,3,4

Tabular Arrays (Objects)

users[3]{id,name,active}:
  1,Alice,true
  2,Bob,false
  3,Carol,true

Strings

# No quotes needed usually
title: Hello World

# Quotes required for:
value: "has: colon"
num: "42"
empty: ""

What is TOON?

Token-Oriented Object Notation (TOON) is a compact, human-readable format that encodes the same data as JSON but uses 30-60% fewer tokens. It's designed specifically for LLM prompts and responses, helping reduce API costs while maintaining the same data model with lossless round-trips.

Token Efficient

Uses indentation instead of braces, minimizes quoting, and collapses uniform object arrays into tables.

LLM Optimized

Explicit [N] lengths and {fields} headers give models clear schema to follow, improving parsing reliability.

JSON Compatible

Same data model as JSON - objects, arrays, strings, numbers, booleans, null. Deterministic, lossless conversion.

JSON vs TOON Example

JSON (more tokens)

{
  "users": [
    {"id": 1, "name": "Alice", "active": true},
    {"id": 2, "name": "Bob", "active": false}
  ]
}

TOON (fewer tokens)

users[2]{id,name,active}:
  1,Alice,true
  2,Bob,false