TOON Validator
Validate TOON syntax and check for errors
TOON Input
Validation Result
What Is a TOON Validator?
TOON (Token-Oriented Object Notation) is a compact format for LLMs and token-limited contexts. It uses shorter syntax than JSON to reduce token count. Like JSON, TOON has strict syntax rules—mismatched brackets, invalid tokens, or malformed structure cause parse errors.
A TOON validator checks whether your document is valid. It parses your TOON and reports any syntax errors with line and position. This tool runs entirely in your browser. Nothing is sent to a server, so it's safe to use with production data, prompts, or sensitive content.
TOON Validation Examples
Valid TOON has correct structure. Invalid TOON often has extra rows or wrong field count. Telecom-themed examples:
Example 1: Valid TOON
Example 2: Invalid TOON (extra row)
Use Valid Sample or Invalid Sample above to load examples into the editor.
How to Use This Tool
Paste or Upload TOON
Copy your TOON and paste it into the left editor. You can also click Upload to load a .toon or .txt file. Use Valid Sample for correct TOON, or Invalid Sample to see what errors look like.
Check the Validation Result
The right panel shows Valid or Invalid. If invalid, it lists errors with line and position so you can pinpoint the problem. Common issues include mismatched brackets, invalid tokens, or malformed structure.
Fix and Revalidate
Fix errors in the input and revalidate. For formatting, use the TOON Formatter. For conversion to JSON or other formats, use TOON to JSON or TOON to YAML.
When TOON Validation Helps
Most developers need validation when working with LLM prompts, AI API responses, or structured data in TOON format. Compared to JSON and YAML, TOON has different syntax. A single syntax error can break parsing or cause unexpected behavior. Running your TOON through here catches errors before you send it to an API or process it further.
If you're converting from JSON to TOON or generating TOON programmatically, validating ensures the output is well-formed. It's also useful before sharing TOON config or prompts with teammates—validating first ensures everyone gets parseable data.
Frequently Asked Questions
What makes TOON invalid?
Mismatched brackets, invalid tokens, malformed strings, or incorrect structure. The validator pinpoints the issue with line and position.
TOON vs JSON validation?
TOON has different syntax (more compact). This validator checks TOON-specific rules. For JSON, use the JSON Validator.
Is my data private?
Yes. Validation runs entirely in your browser. No data is sent to any server. You can confirm this by opening your browser's Network tab.
Can I convert valid TOON to JSON?
Yes. Once validated, use TOON to JSON to convert. The conversion preserves structure and data.
Does it check schema or just syntax?
This tool validates syntax only—whether the TOON is well-formed and parseable. It does not validate against a JSON Schema or custom schema.