JSON to TOON Converter
Convert JSON to TOON format (primary) or YAML/TOML/XML. Reduce LLM token usage by 30-60% with TOON. Validate and format JSON data.
JSON to TOON — Token-Efficient Data for LLMs
TOON (Token-Oriented Object Notation) is a compact data format designed to feed structured data to large language models with far fewer tokens than JSON. This free JSON to TOON converter rewrites your JSON into TOON instantly, right in your browser.
Prefer another format? The same tool also converts JSON to YAML, TOML, and XML, and includes a Format JSON button that validates your input and flags errors before conversion.
TOON, YAML, TOML and XML output
Pick your target format from the dropdown. TOON is the default for token savings, but YAML, TOML, and XML are one click away for configs and APIs.
Validate and format JSON
The Format JSON button pretty-prints your input and highlights invalid JSON immediately, so you never convert broken data.
Free and private
Everything runs locally in your browser with the js-yaml engine — your data is never uploaded to a server. Paste, convert, and copy as much as you like.
How to use
- Paste or type your JSON into the input panel.
- Choose the output format: TOON, YAML, TOML, or XML.
- Click Format JSON first if you want to validate the input.
- Read the converted result and hit Copy Output to use it.
Frequently Asked Questions
What is TOON format?
TOON (Token-Oriented Object Notation) is a compact, human-readable format designed to represent structured data with fewer tokens than JSON, which makes it cheaper and faster to send to large language models.
Does converting JSON to TOON lose data?
No. TOON preserves the full structure and values of your JSON — it is simply a more token-efficient way to write the same data.
Is my JSON uploaded anywhere?
No. Conversion happens entirely in your browser using a local JavaScript engine, so your data never leaves your device.
Can I convert JSON to YAML, TOML, or XML too?
Yes. Use the output format dropdown to switch between TOON, YAML, TOML, and XML at any time.
What happens if my JSON is invalid?
The Format JSON button checks your input and shows an error message when the JSON cannot be parsed, so you can fix it before converting.
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