TOML to JSON Converter

updated 25 April 2026

Before you start

You need some TOML-formatted text or a .toml file from your computer (like Cargo.toml, pyproject.toml, or poetry.lock). I built this tool to be fully TOML 1.0 compliant, so it handles everything from basic key-value pairs to complex nested tables and arrays of tables without breaking a sweat.

Because I'm using a pure-JavaScript parser (smol-toml), the entire conversion happens locally in your browser. I never see your data, and nothing is ever sent to a server, which makes it safe for converting private configuration files. There is no hard file size limit, though extremely large lockfiles might cause a brief stutter as your browser renders the JSON output.

How to use it

1. Paste your TOML into the left pane, or drag and drop a file directly onto the input area.
2. Click Run to start the conversion process.
3. Check the status bar at the bottom for any syntax errors — if your TOML is invalid, I'll show you exactly where.
4. Review the JSON result in the right-hand pane.
5. Click Copy result to put the output on your clipboard.

Example

Input (TOML):

[server]
port = 8080
enabled = true
tags = ["api", "prod"]

Output (JSON):

{
  "server": {
    "port": 8080,
    "enabled": true,
    "tags": ["api", "prod"]
  }
}

Notice that types like integers, booleans, and arrays map perfectly → JSON, while TOML-specific types like dates are stringified.

Tips & common pitfalls

• Comments are stripped. JSON doesn't support comments, so any lines starting with # in your TOML are discarded during the conversion.
• Dates become strings. TOML has native date types, but JSON does not. I convert them to ISO 8601 strings so they remain machine-readable and easy to parse.
• Dotted keys create objects. In TOML, a key like site.name = "My Site" is a shortcut for a nested table; the JSON output will show this as a nested object.
• Check the status bar. If the output doesn't appear, look at the bottom of the tool. TOML is quite strict about quoting and structure, and the parser will report the specific line causing trouble.

Troubleshooting

Related tools

• JSON to TOMLTurn JSON objects back into clean, readable TOML documents.
• TOML ValidatorA dedicated checker to verify your config against the TOML 1.0 spec.
• TOML FormatterFix messy indentation and normalize the layout of your TOML files.
• TOML to YAMLConvert your configuration to YAML 1.2 if you need to preserve comments.

See also: if you need to do something adjacent on this site, try JSON to TOML to convert JSON to TOML, TOML to YAML to convert TOML to YAML, or YAML to TOML to convert YAML to TOML.

Frequently asked questions