JSON / TOML Converter

Tool guide

What is JSON / TOML Converter?

JSON and TOML Converter moves structured data between API-oriented JSON and project configuration. A mature parser handles tables, nested tables, arrays, strings, numbers, booleans, and dates while making the null, comment, and formatting boundaries explicit instead of relying on fragile textual replacement. Common workflows include the following. Convert JSON configuration into TOML used by project tooling. Turn TOML into formatted JSON for review or API-oriented processing. Inspect how arrays, tables, and dates map between the formats. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.

When to use it

Convert JSON configuration into TOML used by project tooling.
Turn TOML into formatted JSON for review or API-oriented processing.
Inspect how arrays, tables, and dates map between the formats.

How to use it

Choose the direction and paste a complete document.
Load a realistic example to check tables and arrays.
Run the conversion and read warnings.
Review dates, null, and comment loss before copying.
Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.

Runnable examples

The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.

Example 1

{"title":"JSONLane","server":{"host":"127.0.0.1","ports":[80,443]},"release":{"tools":40,"ready":true}}

Example 2

title = "JSONLane"

[server]
host = "localhost"
ports = [80, 443]

[release]
tools = 40
ready = true

Input rules

JSON to TOML requires a strict JSON root object.
TOML input must follow syntax supported by the bundled parser.
JSON null and values without a safe TOML mapping are rejected.
Text input is counted before processing and is limited to 1,000,000 characters on this page; file modes apply the separate file limit shown in the workspace.
JSON to TOML requires a root object and TOML cannot represent null.

Output rules

TOML output uses stable parser formatting for keys and tables.
TOML dates become normalized ISO strings in JSON.
Comments, original whitespace, and quote style are not retained.
Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
Comments, key quoting, and original layout are not retained.

Limitations and cautions

JSON to TOML requires a root object and TOML cannot represent null.
Comments, key quoting, and original layout are not retained.
Dates are normalized as strings in JSON.

How your data is handled

All parsing, conversion, binary encoding, and intermediate data remain in the current browser tab. JSONLane does not upload the input or retain it after refresh or close.

FAQ

Is JSON or TOML content uploaded?

No. Parsing, conversion, and output generation remain in the current browser tab.

Is every round trip lossless?

No. Formats differ in types, comments, ordering, and binary capabilities; the page documents the important losses.

Why are some inputs rejected?

Unsafe integers, dangerous keys, excessive depth, and values with no clear target representation are rejected instead of silently rewritten.

How are TOML dates represented?

They are normalized to ISO strings in JSON. Verify them again if the destination application expects a native date type.

Why can null not become TOML?

TOML has no standard value equivalent to JSON null, so the tool rejects it instead of substituting an empty string.

Are arrays of tables supported?

Common object arrays map through the TOML parser, but complex configuration should still be validated in the destination application.