TOON to JSON Converter

TOON (Token-Oriented Object Notation) is a compact indented format designed to minimize token usage when feeding structured data to large language models. By stripping JSON's braces, brackets, and quotes, TOON cuts token counts by 30–60% — directly reducing API costs and latency.

When should you use TOON?

Use TOON whenever you're sending structured data to an LLM (GPT-4, Claude, Gemini) and want to fit more content into a context window or pay less per request. It's especially valuable for prompts with large nested config, user records, or product catalogs.

How TOON maps back to JSON

TOON uses YAML-like indentation: keys with colons, values inline, arrays with dashes. Our parser walks the indentation tree, infers types (boolean, number, null, string), and reconstructs the original JSON object faithfully.

Lossless round-tripping

TOON ↔ JSON is lossless for standard data types. Strings, numbers, booleans, null, arrays, and nested objects all survive conversion in both directions, so you can safely use TOON as your wire format and JSON for processing.

What our parser handles

• Indentation-based nesting (2-space convention)
• Inline comments starting with #
• Booleans (true/false), null (~ or null)
• Integer and float type inference
• Quoted strings (single or double)
• Arrays declared with [] then dash items

Whether you're prototyping prompts, optimizing production AI calls, or debugging LLM output, this free parser gives you the JSON view of your TOON data instantly.