TOON Formatter & Validator
Validate TOON (Token-Oriented Object Notation) data and convert it back to JSON. Check syntax and preview parsed output.
Features
- ✓Convert TOON back to formatted JSON
- ✓Validate TOON syntax with clear error messages
- ✓Parse tabular format ({fields}[N] with tab-separated rows)
- ✓Parse key-value format (YAML-style indented objects)
- ✓Handle primitive arrays, nested objects, and quoted strings
- ✓Copy parsed JSON output to clipboard
How to Use
- 1Paste your TOON data in the input area or click "Load Sample"
- 2Click "Convert to JSON" to parse the TOON and get formatted JSON output
- 3Click "Validate" to check if the TOON syntax is correct without converting
- 4Copy the JSON output using the copy button
Examples
Input
{name,age}[2]
Alice 30
Bob 25Output
[{"name":"Alice","age":30},{"name":"Bob","age":25}]Input
host: localhost port: 8080 ssl: true
Output
{"host":"localhost","port":8080,"ssl":true}What Is TOON and How to Parse It?
TOON (Token-Oriented Object Notation) is a compact data format designed to minimize tokens when sending structured data to LLMs. This tool handles the reverse direction: converting TOON back to standard JSON so you can process, validate, or inspect the data with familiar tools.
The tabular format is TOON's most distinctive feature. A header like {name,age,city}[3] declares the field names and row count, followed by tab-separated values — one row per line. This tool parses the header, splits each row by tabs, and reconstructs the original JSON array of objects.
The key-value format resembles YAML: each line has a key followed by a colon and value. Nested objects use indentation. This tool parses the indentation structure to reconstruct nested JSON objects. Values are automatically typed — numbers become numbers, "true"/"false" become booleans, and "null" becomes null.
Validation checks that the TOON structure is syntactically correct without producing output. This is useful for verifying TOON data before sending it to a parser or LLM. The validator reports specific errors like mismatched row counts or malformed headers.
All parsing happens in your browser. Your TOON data is never sent to any server, making this safe for proprietary data, internal API responses, and confidential datasets.