TOON Validator
Validate TOON syntax and check for errors
TOON Input
Validation Result
What is TOON Validator?
Need to check if your TOON (Token-Oriented Object Notation) syntax is correct? This tool validates your TOON data instantly, checking for syntax errors, structural issues, and formatting problems. Perfect for catching errors before using TOON in production or sending it to LLMs.
According to the TOON documentation, proper validation ensures data integrity and prevents errors in downstream processing. Our validator uses the official TOON library to check your syntax, validate array lengths, verify tabular row counts, and ensure proper structure. If there are errors, we'll show you exactly where they are.
Everything happens in your browser – your data stays private. Validate, review results, and fix issues right away. You can also format your TOON using our TOON Formatter or convert it to JSON with our TOON to JSON converter.
What Makes This Tool Different
Real-Time Validation
Validation happens instantly as you type. See results immediately – no need to click a button. Catch errors before they become problems.
Detailed Error Messages
Invalid TOON? We'll show you exactly what's wrong, where it's wrong, and how to fix it. Clear error messages with approximate line numbers help you debug quickly.
Structure Analysis
Valid TOON? We'll show you the document type (object, array, primitive), item counts, keys, and structure information. Perfect for understanding your data.
File Upload Support
Got a TOON file? Just upload it. Works with .toon and .txt files. No need to copy-paste – just drag and drop or click upload.
Visual Feedback
Clear visual indicators show validation status. Green badge for valid TOON, red badge for invalid. See results at a glance.
Common Error Help
When errors occur, we provide helpful tips about common TOON mistakes – missing array lengths, mismatched row counts, invalid delimiters, and more.
How It Works
Paste or Upload TOON
Paste your TOON data into the left editor, or click "Upload" to load a file. You can also click "Valid Sample" to see example TOON format. The validator accepts any TOON structure.
Automatic Validation
As soon as you paste, the validator checks your TOON syntax and displays results on the right. Valid TOON shows structure information, invalid TOON shows detailed error messages.
Review Results
Check the validation badge (green for valid, red for invalid) and review the detailed output. Fix any errors, then validate again. Copy results if needed.
When You'd Actually Use This
Before LLM Processing
Sending TOON data to LLMs? Validate it first to ensure it's correct. Invalid TOON can cause LLM errors or incorrect parsing, wasting tokens and API calls.
Debugging
Something not working with your TOON data? Validate it to find syntax errors, structural issues, or formatting problems. Clear error messages help you fix issues fast.
Code Review
Reviewing TOON files in pull requests? Validate them to ensure they're syntactically correct before merging. Catch errors early in the development process.
Learning TOON
Learning TOON syntax? Use the validator to check your examples. See what's valid, what's invalid, and understand the error messages to improve your TOON skills.
Common Questions
Is my TOON data stored?
No. All validation happens in your browser using the @toon-format/toon library. Your data never leaves your computer.
What does the validator check?
We check TOON syntax, array length markers, tabular row counts, delimiter usage, indentation, and overall structure. Everything needed to ensure valid TOON format.
Can I validate invalid TOON?
Yes! That's the point. Paste invalid TOON and we'll show you exactly what's wrong, where it's wrong, and provide helpful tips to fix it.
What information does valid TOON show?
For valid TOON, we show document type (object, array, primitive), item counts, keys (for objects), and structure information. Helps you understand your data better.
How accurate are error line numbers?
We provide approximate line numbers based on error position. They're usually accurate, but for complex errors, the error message itself is more reliable than the line number.
Does validation affect my data?
No. Validation is read-only. We only check your TOON syntax – we don't modify, store, or change your data in any way.
Other TOON Tools You Might Need
Validation is just one TOON task. Here are other tools that work well together:
Want to learn more about TOON? Check out the official TOON Tools website or read the TOON documentation.