TOON to JSON Converter — Decode Token-Oriented Object Notation

Paste TOON and get pretty JSON in your browser. Strict validation is on by default. TOON is for prompt payloads, not general storage formats. Spec: toonformat.dev. Round-trip with JSON → TOON.

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Decode TOON back to JSON
Validate and pretty-print TOON locally. Strict mode catches schema mismatches; lenient mode helps debug hand-edited files.

How decoding works

We lazy-load @toon-format/toon v4.1.1 and call decode with your options. Successful output is JSON.stringify(value, null, 2). Parse errors stay in-pane with SDK messages (and line numbers when available).

Options that change decoding

Strict validation
When enabled, the decoder rejects duplicate keys and length mismatches. Disable only for debugging hand-edited TOON.
Expected indent
Number of spaces per indentation level in the TOON source. Must match how the file was encoded.

FAQ

Strict mode, errors, and scope

What does strict validation do?

Strict mode enforces array lengths and tabular row counts per the TOON spec. Turn it off only when debugging edited files.

What changes in lenient mode?

Duplicate keys become last-write-wins and some length checks relax. Output may not match the original authoring intent.

Can I store APIs responses as TOON?

No — use JSON or YAML for interchange. TOON is for LLM prompts.

How do I fix parse errors?

Read the line called out in the error card, compare against the tabular sample, or re-encode from JSON.

Is my TOON uploaded?

No. Decoding runs locally in your browser.

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Token counting, pricing estimates, and context-window fit — 100% browser-local.

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