JSONToonPro
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Cut LLM Costs by 60%
with TOON Format

Paste your JSON and get a compact TOON version in seconds. Your OpenAI, Claude and Gemini bills shrink automatically.

Start Converting Free Calculate My Savings
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60%

Token Reduction

$90K+

Annual Savings

100K+

Conversions Run

4

LLM Providers

How It Works

Three Steps to Lower API Bills

No account needed. No configuration. Just paste, convert and save.

  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 straight into your LLM prompt. See your exact token count drop and watch your monthly API bill follow.

Free Tool

JSON to TOON Converter

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

Privacy-FirstReal-TimeNo SignupFree Forever
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.

Free Calculator

How Much Could You Save?

Enter your monthly token volume and see your exact 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: $5/1M tokens

Monthly Token Volume

Expected Token Savings

45%

Great

Mixed objects — strong savings

5% min65% max

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

Monthly Cost Before

$5.00

1M tokens/mo

Monthly Cost After

$2.75

550K tokens/mo

Monthly Savings

$2.25

450K tokens saved

Annual Savings

$27.00

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 cut LLM costs 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 see exact cost savings for GPT-4o, Claude Sonnet and Gemini Pro side by side.

  • Your Data Stays Private

    All conversion happens inside your browser. Nothing is sent to any server, ever. No account, no tracking.

  • 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.

FAQ

Common Questions

Everything you need to know before you start saving.

What exactly is TOON format?
TOON (Token-Oriented Object Notation) is a compact way to represent JSON arrays as a table. Instead of repeating key names on every row, it writes them once as column headers. That single change cuts token usage by 30 to 60 percent on most real-world data.
Is my data safe?
Yes. All conversion runs entirely in your browser using JavaScript. Nothing is sent to any server, nothing is stored, and nothing is logged. JSONToonPro works fully offline once the page has loaded.
Will my LLM understand TOON format?
Every major model does — GPT-4o, Claude, Gemini, LLaMA, Mistral and others. TOON is plain text with a simple structure. Add one line to your system prompt explaining the format and the model handles it without issue.
How much can I realistically save?
Uniform arrays like database rows or API lists typically save 50 to 65 percent. Mixed objects save 30 to 50 percent. Even deeply nested structures improve by 15 to 30 percent. Enter your monthly token volume in the calculator above to see your exact dollar figure.
Can I convert TOON back to JSON?
Yes, full round-trip conversion with no data loss. Switch the converter to TOON to JSON mode and you get back perfectly formatted JSON instantly.
Is JSONToonPro really free?
The core converter is free with no usage limits and no account required. Pro features including API access, batch ZIP processing, AI-assisted optimization and team workspaces are coming in a paid tier.

Ready to Stop Overpaying for Tokens?

Free forever, no account needed. Paste your JSON and see exactly how much you save before you commit to anything.

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No credit card. No account. No limits on the free tier.