TONL to TOML Converter

Input TONL

or drop a file anywhere

Output TOML

Your TOML appears here as you type.

Paste data to see token savings

Convert TONL to TOML with our free online converter.

Example: TONL input and real TOML 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"

TOML output (355 characters)

[[events]]
latencyMs = 42
level = "info"
service = "auth"
ts = "2026-09-30T08:12:04Z"

[[events]]
latencyMs = 310
level = "warn"
service = "billing"
ts = "2026-09-30T08:12:09Z"

[[events]]
latencyMs = 38
level = "info"
service = "auth"
ts = "2026-09-30T08:12:15Z"

[[events]]
latencyMs = 1204
level = "error"
service = "search"
ts = "2026-09-30T08:12:21Z"

TOML output is 56% larger 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).

TONL to TOML: what changes

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 TOML: TOML requires a top-level table: a root-level array is wrapped as [[data]]. Arrays of objects become [[name]] array-of-tables blocks, and null values are silently dropped because TOML has no null.

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 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 →

Why Convert TONL to TOML?

Use TOML for application configuration, especially in Python (pyproject.toml) or Rust (Cargo.toml) projects. It has explicit types and no ambiguity.

TONL to TOML: Frequently Asked Questions

How do I convert TONL to TOML?

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

Is the TONL to TOML converter free?

Yes. Converting TONL to TOML 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 TOML?

Convert TONL to TOML with our free online converter.

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

TOML requires a top-level table: a root-level array is wrapped as [[data]]. Arrays of objects become [[name]] array-of-tables blocks, and null values are silently dropped because TOML has no null.

Is my data safe when I convert TONL to TOML?

Yes. The TONL to TOML 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.