Data Converter & Token Analyzer
Convert between JSON, YAML, TOML, and TOON formats, and instantly calculate LLM Token usage and savings.
About Data Converter
A tool designed for LLM Prompt Engineering and data exchange. Besides common JSON/YAML/TOML conversion, we introduce TOON format, aiming to significantly reduce Token usage without sacrificing readability.
Token Calculation
This tool uses tiktoken library with cl100k_base encoding. This is the standard tokenizer used by OpenAI GPT-4, GPT-3.5-turbo, text-embedding-ada-002, ensuring high accuracy with actual API usage.
TOON Savings
For structured data with high repetition (like arrays of objects), JSON wastes many tokens on repeated keys. TOON format extracts headers and simplifies symbols, usually saving 30% ~ 60% of token costs, allowing you to fit more data into the Context Window.
Minified Mode
When 'Minified Mode' is on, the tool automatically removes all unnecessary whitespace and newlines (especially effective for JSON and TOON). While this reduces human readability, it is the ultimate token saving solution for AI models, suitable for tight Context Windows.
Supported Formats
JSON (JavaScript Object Notation)
Web APIConfig Most common data exchange format. High compatibility, but verbose syntax (quotes and brackets) results in high token usage.
YAML (YAML Ain't Markup Language)
CI/CDKubernetes Structure presented via indentation, excellent readability. More compact than JSON, suitable for configs. However, LLMs sometimes hallucinate due to indentation errors.
TOML (Tom's Obvious, Minimal Language)
RustPython INI-like format with clear structure. Very compact for flat configs, but can become verbose for deep nested data.
TOON (Token-Oriented Object Notation)
LLM OptimizationSince 2025Custom format (created in 2025). Optimized for 'arrays of objects', like CSV but type-safe. Defines headers via keys[...] to remove repeated keys, offering the best price-performance ratio for AI reading.
Privacy & Security Statement
Your data security is our top priority. This tool uses Client-side Computing technology, meaning all processing happens instantly on your device (phone or computer).
This means: No content you enter is ever uploaded to the internet or our servers. Whether it's confidential documents, private diaries, or code, you can safely paste and process it here.