JSON to TOML

Convert JSON into TOML, the configuration format used by Cargo, pyproject, and many static site tools. Nested objects become tables and arrays of objects become arrays of tables. TOML has no null, so null values are dropped and listed in a warning.

JSON

TOML

Result will appear here

Ready. Press Convert or Ctrl+Enter.

How to use the JSON to TOML

Paste a JSON object (TOML needs an object at the top).
Press Convert.
Copy the TOML output.

Example

The notes key is null in the sample, so it is dropped with a warning.

{
  "name": "json-utils",
  "version": "1.0.0",
  "private": false,
  "tags": ["json", "tools"],
  "author": { "name": "Ada", "active": true },
  "score": 9.5,
  "notes": null
}

Frequently asked questions

Why did my null values disappear?

TOML has no null type. Dropping them is the only honest option, and the tool warns you each time.

Why did conversion fail on my array?

TOML arrays must hold one type. Mixed type arrays and arrays mixing tables with scalars cannot be represented.