TOML to TOON Converter

Input TOML

or drop a file anywhere

Output TOON

Your TOON appears here as you type.

users[3]{id,name,role}:
  1,Alice,admin
  2,Bob,user
  3,Cleo,user

Field names once, then one row per record.

Paste data to see token savings

Convert TOML to TOON with our free online converter.

Example: TOML 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.

TOML input (155 characters)

[package]
name = "invoice-tool"
version = "0.3.2"
edition = "2021"

[dependencies]
serde = "1.0"
tokio = "1.40"

[profile.release]
lto = true
opt-level = 3

TOON output (162 characters)

package:
  name: invoice-tool
  version: 0.3.2
  edition: "2021"
dependencies:
  serde: "1.0"
  tokio: "1.40"
profile:
  release:
    lto: true
    "opt-level": 3

TOON output is 5% larger than the TOML input. The same data is 165 characters as minified JSON and 244 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 43% fewer tokens than JSON (42.6%) according to the official TOON benchmark.

TOML to TOON: what changes

Reading TOML: A TOML document always parses to a table (an object), never a bare array. Datetimes are a TOML-native type and come out as ISO 8601 strings.
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 TOML

TOML is a config file format with explicit types. It's the official format for Python's pyproject.toml and Cargo's Cargo.toml.

✓Explicit types
✓Standard in Python/Rust
✓Unambiguous
✓Easy to parse

Full TOML Documentation →

About TOON

TOON (Token-Oriented Object Notation) is an indentation-based format designed for LLM prompts. It uses about 43% fewer tokens than JSON on average (42.6% in the official TOON v4.1 benchmark), ranging from about 33% on mixed/nested structures to about 59% on flat uniform tables.

✓About 43% fewer tokens than JSON on average
✓Tabular rows for uniform arrays
✓Lossless round trip to JSON
✓Readable without tooling

Full TOON Documentation →

Why Convert TOML to TOON?

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

TOML to TOON: Frequently Asked Questions

How do I convert TOML to TOON?

Paste your TOML 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 TOML to TOON converter free?

Yes. Converting TOML 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 TOML to TOON?

Convert TOML to TOON with our free online converter.

What should I watch out for when converting TOML to 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.

Is my data safe when I convert TOML to TOON?

Yes. The TOML 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.