Convert JSON to TOON format - optimized for LLM prompts with ~40% fewer tokens
Try the JSON to TOON converter with sample data
Convert JSON to TOON format - optimized for LLM prompts with ~40% fewer tokens
Try the JSON to TOON converter with sample data
Token-Oriented Object Notation (TOON) is a compact data format designed specifically for Large Language Models, combining the readability of YAML with the efficiency of CSV-style arrays.

Uses 30-60% fewer tokens than standard JSON, reducing API costs significantly
Lossless round-trips with JSON data model - convert back anytime
73.9% retrieval accuracy vs JSON's 69.7% - optimized for AI parsing
Uses indentation instead of braces, minimizes quoting for cleaner output
Uniform arrays collapse into compact tables - perfect for repeated structures
Try it via CLI:npx @toon-format/cli *.json
Official TOON format specification and documentation
Understand the key differences between JSON and TOON formats to choose the right one for your LLM applications
| Format | Accuracy | Token Count | Token Savings |
|---|---|---|---|
| TOON | 73.9% | 2,744 | 39.6% |
| JSON | 69.7% | 4,545 | — |
* Benchmark based on GPT-4 Turbo (gpt-4-1106-preview) testing on diverse datasets
💡 Pro Tip: Convert your JSON to TOON above and save 30-60% on token costs for your LLM applications
Get answers to common questions about converting JSON to TOON
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