What TOON compresses well
Repeated object keys are lifted into one header line, then each row keeps only values. That makes it useful as a JSON compressor for arrays of objects, API payloads, product catalogs, logs, and prompt-ready JSON.
JSON to TOON Converter - Reduce
LLM API costs
Convert JSON to TOON serialization format and reduce LLM tokens by 30-60%. Lower GPT token costs and Claude API costs with our free browser-based converter.
JSON Input
Waiting for input
JSON is parsed locally in your browser.
0 estimated source tokens
TOON Output
Compact notation with table blocks for repeated object arrays.
No output yet
Approximate token estimate updates after each conversion.
0 estimated result tokens
No token delta yet
How savings are estimated
The page uses a simple approximate token estimate based on text length, then shows an example cost comparison at $30 per million tokens for AI prompts, LLM payloads, and structured JSON requests.
Round-trip support
Switch to TOON -> JSON to reverse the converter output and verify structure before you move it into prompts, docs, examples, or JSON optimization workflows.
FAQ
Does this change the meaning of my JSON?
The goal is structural compression, not semantic compression. The generated TOON keeps enough information for this tool to reconstruct the original JSON shape.
Will every JSON document compress well?
No. TOON helps most when many objects reuse the same keys. Very small JSON or highly irregular nested structures may see smaller gains.
Can I use this output directly in prompts?
Yes, that is the main idea. The banner gives an approximate reduction estimate so you can compare source and TOON payload size quickly.
Who is this tool useful for?
It is useful for developers, prompt engineers, API users, and anyone trying to compress JSON for ChatGPT, Claude, Gemini, or other language model workflows.
What search terms match this tool?
People may look for this as a JSON compressor, prompt token reducer, JSON prompt optimizer, JSON array compressor, TOON converter, TOON parser, or TOON to JSON converter.