JSONToonPro
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JSON formatter, beautifier, and TOON tools

JSON Formatter and Beautifier. Convert to TOON.

The online JSON Formatter, JSON Beautifier, and JSON to TOON Converter for developers. Format JSON, validate syntax, minify, and compress repeated records into compact TOON for GPT, Claude, Gemini, or any LLM.

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Client-side conversionToken estimateRound-trip JSON
JSONInput
{  "users": [    { "id": 1, "name": "Alice" },    { "id": 2, "name": "Bob" }  ]}
TOONOutput
users[2]{id,name}:1,Alice2,Bob
EstimateCompare token usage before prompt use.
PrivateConversion runs in the browser.
How It Works

Three Steps to Lower API Bills

Paste JSON, convert locally, then compare the token estimate before using the output.

  1. Paste Your JSON

    Drop in any JSON from an API response, database export, or config file. The editor accepts any valid JSON, no matter how nested.

  2. Convert in Milliseconds

    The engine strips repeated key names and restructures your data into compact TOON format. Everything runs in your browser, nothing leaves your machine.

  3. Use It and Save

    Copy the TOON output into your LLM prompt. Compare token counts and estimate how the smaller prompt can affect your monthly API bill.

Browser Tool

JSON to TOON Converter

Paste your JSON on the left and get compact TOON on the right. Everything runs in your browser, so nothing is sent anywhere.

Privacy-FirstReal-TimeToken EstimateRound Trip
Examples:
JSON Input
TOON Output
Side by Side

JSON vs TOON

Same data. 74% fewer tokens. Your LLM reads it just fine.

JSON: Verbose
~85 tokens
[
  {
    "name": "Alice",
    "age": 30,
    "city": "New York"
  },
  {
    "name": "Bob",
    "age": 25,
    "city": "London"
  },
  {
    "name": "Carol",
    "age": 35,
    "city": "Tokyo"
  }
]
TOON: Optimized
~22 tokens, 74% saved
[
name,age,city
Alice,30,New York
Bob,25,London
Carol,35,Tokyo
]

JSON writes "name", "age", "city" three times, once per row. TOON writes them once as headers and reuses them for every row. The more rows you have, the bigger the saving.

Savings Calculator

How Much Could You Save?

Enter your monthly token volume and estimate savings across GPT-4o, Claude, and Gemini before you change a single line of code.

LLM Cost Calculator

Enter your volume and see your real savings before changing any code.

LLM Provider

Input price: $2.5/1M tokens

Monthly Token Volume

Expected Token Savings

45%

Great

Mixed objects with strong savings

5% min65% max

Use the converter above to find your actual savings percentage for your specific JSON data.

Monthly Cost Before

$2.50

1M tokens/mo

Monthly Cost After

$1.38

550K tokens/mo

Monthly Savings

$1.13

450K tokens saved

Annual Savings

$13.50

per year at this volume

Token usage comparison45% reduction with TOON
TOON tokens used (55%)
Tokens saved (45%)

Annual savings across all providers

Features

Built for Developers Who Ship

Everything you need to estimate LLM token savings today, with more power available when you need it.

  • Converts as You Type

    No button to press. Paste your JSON and the TOON output and token count update instantly on every keystroke.

  • Real Dollar Savings

    Enter your monthly token volume and estimate cost savings for GPT-4o, Claude Sonnet, and Gemini Pro side by side.

  • Your Data Stays Private

    All core conversion happens inside your browser. JSON input is not sent to a server for conversion.

  • Works Both Ways

    Convert JSON to TOON or TOON back to JSON with full round-trip accuracy. Switch modes with one click.

  • Advanced Controls

    Set custom delimiters, adjust indentation, exclude specific fields, and add length markers for fine-tuned output.

  • Works with Any LLM

    TOON output drops straight into prompts for GPT-4o, Claude, Gemini, LLaMA, Mistral and every other major model.

  • Pro

    Batch Processing

    Upload a ZIP of JSON files and download everything converted in one go. No repetitive copy-pasting.

  • Pro

    AI Optimizer

    Claude scans your JSON structure and suggests field exclusions and formatting tweaks that cut tokens even further.

  • Pro

    Savings Dashboard

    Track tokens saved and money recovered across all your conversions over time. See the cumulative impact.