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TONL to TOON

Convert TONL to TOON with our free online converter.

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Example: TONL input and real TOON output

The output below was generated by the same conversion code the converter uses, run on this sample when the page was built.

TONL input (228 characters)

#version 1.0
root:
  events[4]{latencyMs,level,service,ts}:
    42,info,auth,"2026-09-30T08:12:04Z"
    310,warn,billing,"2026-09-30T08:12:09Z"
    38,info,auth,"2026-09-30T08:12:15Z"
    1204,error,search,"2026-09-30T08:12:21Z"

TOON output (199 characters)

events[4]{latencyMs,level,service,ts}:
  42,info,auth,"2026-09-30T08:12:04Z"
  310,warn,billing,"2026-09-30T08:12:09Z"
  38,info,auth,"2026-09-30T08:12:15Z"
  1204,error,search,"2026-09-30T08:12:21Z"

TOON output is 13% smaller than the TONL input. The same data is 329 characters as minified JSON and 505 as pretty-printed JSON. Sizes are character counts, not tokens: token counts depend on the model's tokenizer (see the tokenizer comparison). Across larger datasets, TOON averages about 40% fewer tokens than JSON according to the official TOON benchmark.

TONL to TOON: what changes

Moving tabular TONL to TOON drops the #version header and root wrapper while keeping the rows, so the result is slightly shorter and can go straight into a prompt.
Reading TONL: TONL documents start with a #version line and wrap the data in root. The TONL encoder writes object keys in alphabetical order, so the original key order is not kept.
Writing TOON: TOON saves the most on arrays of objects that share the same fields: they collapse into one header plus one row per record. Nested or non-uniform objects are written as indented key: value lines and save much less.

About TONL

TONL (Token-Optimized Notation Language) is a compact text format that maps one-to-one to JSON and ships with a query API, schema validation, and streaming. Savings are roughly 32-45% versus JSON in the TONL project's own measurements.

✓Lossless round trip to JSON
✓Query and aggregation API
✓Schema validation (TSL)
✓Streaming for large files

Full TONL Documentation →

About TOON

TOON (Token-Oriented Object Notation) is an indentation-based format designed for LLM prompts. It uses about 40% fewer tokens than JSON on average (39.9% in the official TOON benchmark), ranging from ~22% on mixed/nested structures to ~59% on uniform tables.

✓About 40% fewer tokens than JSON on average
✓Tabular rows for uniform arrays
✓Lossless round trip to JSON
✓Readable without tooling

Full TOON Documentation →

Other Conversions

TONL to JSON TONL to YAML TONL to TOML TONL to CSV TONL to XML TONL to Protobuf

Why Convert TONL to TOON?

Use TOON when building LLM-powered applications, optimizing API costs, or when you need compact, readable data for AI models.

TONL to TOON: Frequently Asked Questions

How do I convert TONL to TOON?

Paste your TONL into the editor on json2toon.co. The tool detects the input and produces TOON instantly, then you copy the result. Conversion runs entirely in your browser, so nothing is uploaded to a server.

Is the TONL to TOON converter free?

Yes. Converting TONL to TOON on json2toon.co is free with no account, signup, or usage limit. A free public API is also available for automated, programmatic conversion.

Why convert TONL to TOON?

Convert TONL to TOON with our free online converter.

What should I watch out for when converting TONL to TOON?

Moving tabular TONL to TOON drops the #version header and root wrapper while keeping the rows, so the result is slightly shorter and can go straight into a prompt.

Is my data safe when I convert TONL to TOON?

Yes. The TONL to TOON conversion happens client-side in your browser. Your source data stays on your device and is never sent to or stored on a server, which makes it safe for private or sensitive payloads.