JSON to TOON Converter

Indentation-based structure, no braces. Plain fields are key: value lines, primitive arrays inline like tags[3]: a,b,c, and uniform object arrays become a header such as products[4]{id,sku,name,price} followed by one delimited row per record. The declared lengths and field list also give the model something to validate against.

Expect 30 to 60 percent on flat, table-like data such as query results or product catalogs, because that's where repeated keys dominate JSON's size. Deeply nested or non-uniform data saves much less, sometimes nothing. The savings panel measures your actual payload, so you don't have to guess.

No, and it's worth being clear about that: it's a young format with a public spec maintained on GitHub, not an RFC. It's a sensible choice for prompt payloads you control end to end, and a poor choice for public API contracts. Since this tool converts both directions, adopting it isn't a one-way door.

Yes, exactly. Press Swap direction, paste the TOON, and the decoder rebuilds the same structure with strings, numbers, booleans, nulls, objects, and arrays intact. Round-tripping is lossless, which is what separates a real serialization format from mere prompt shorthand.

Comma is the readable default. Tab frequently wins on token count because tokenizers tend to merge a tab into one token and tab characters rarely appear inside data, so fewer cells need quoting. Pipe sits in between. The choice is declared in the array header, so decoding works the same regardless.

Reliably, yes, because it reads like a blend of YAML and CSV, both heavily represented in training data. The explicit array lengths and field headers help the model keep rows straight. One line in your prompt saying the data is in TOON format removes any remaining ambiguity.

It's a heuristic modeled on GPT-style BPE tokenization, so absolute numbers will differ a bit per model. Both sides of the comparison use the same estimator, though, which makes the percentage a fair relative measure. For billing-grade numbers, run both versions through your provider's own tokenizer.

Yes: anything consumed by a strict JSON parser, like function-calling schemas, tool outputs, or REST payloads, should stay JSON. The same goes for deeply nested config-like data, where TOON's tabular advantage disappears. Use it where it wins, which means large flat datasets pasted into prompts.

It's a focused json converter rather than a catch-all: it turns JSON into TOON and back. If you need JSON reshaped for spreadsheets or XML, the JSON to CSV and JSON to XML pages handle those directions instead.

As a json converter online aimed at LLM input, it rewrites JSON as TOON so repeated keys stop costing tokens. It's a niche json tool, not a Swiss Army knife, and that focus is why the savings panel can measure the difference for your exact payload.

It sits alongside the JSON Formatter, JSON Validator, and JSON to CSV as one of the json developer tools on the site, each doing one job well. This one is the json file converter for the JSON to TOON direction; paste a file's contents and convert, with no upload.

Not on this page, because the input side needs valid JSON before it can make TOON. For a true text to json converter, shape your text into JSON with the JSON Formatter first, then bring the result back here to compress it.

Not directly. A txt to json converter would read a loose .txt file, but this tool expects JSON already. Once you convert text to json in the Formatter, paste that JSON here to get TOON out.

No. A word to json converter or a string to json converter parses arbitrary input into JSON, which is a separate job from what this page does. It assumes you already have valid JSON and want TOON on the other side.

No. A js to json converter reads a JavaScript object literal with unquoted keys, and this tool needs strict JSON instead. Clean the object into JSON with the Formatter, then convert it to TOON here.

No builder UI lives here, so it isn't a json creator or a json maker with fields to fill in. Paste JSON that already exists, and this page converts it to TOON.

No. A json to object converter parses JSON into a runtime object, which is what your language's own parser handles. This page converts JSON text into TOON text, not into a live object.

Yes. Press Swap direction, paste your TOON, and it will convert to json format and print clean, indented JSON. Save that output as a .json file and the convert to json file step is done, with the structure identical to what you started with.

No. To convert json to json string, meaning JSON escaped so it can sit inside another string, use the JSON Formatter rather than this page. Here the goal is the opposite: convert json format into compact TOON, or expand TOON back to readable JSON.