Free browser-based tool

TOON Validator and Formatter

Validate TOON 4.1 strictly, inspect line-aware decoding errors, preview JSON structure, and format valid documents through canonical re-encoding.

Strict TOON 4.1 validation Validation uses strict decode from official codec package 4.1.1
Canonical formatted TOON
Guide

Validate TOON structure strictly and format only valid documents

TOON validation checks syntax and structural rules such as indentation, headers, declared array counts, row widths, escapes, duplicate keys, and trailing root content.

Formatting is performed only after a strict successful decode. ArrayText then re-encodes the decoded JSON value into canonical TOON output without silently repairing invalid source text.

Common questions

TOON Validator and Formatter FAQ

What version does this validator support?

It uses official package 4.1.1 for TOON Working Draft specification 4.1.

Does validation check my application schema?

No. It validates TOON syntax and structure, not JSON Schema, business rules, or required application fields.

Can the formatter fix invalid TOON?

No. Invalid documents receive diagnostics. Canonical formatting becomes available only after strict decoding succeeds.

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