Which TOML features are supported?

It supports key = value pairs, basic and literal strings, integers and floats, booleans, dotted keys, [tables], [[arrays of tables]], inline arrays and

How accurate is the parsing?

The parser follows the TOML v1.0.0 syntax for the supported subset, including underscore-separated numbers and quoted keys, and reports an error rather than guessing when it sees an unsupported construct.

Is my TOML sent anywhere?

No. The conversion runs entirely in your browser with JavaScript — your config never leaves your device.

What does an array of tables become in JSON?

A [[servers]] array of tables becomes a JSON array of objects under the servers key, with each [[servers]] block adding one object to that array.

How are dotted keys handled?

A dotted key like database.port creates nested objects, so it becomes a nested mapping such as database then port in the JSON output.

Why does it error on dates or multi-line strings?

Those constructs are intentionally out of scope for this focused parser. Rather than silently mis-parsing them, it raises a clear error so you know to convert them manually or use a full TOML library.

Can I paste a Cargo.toml or pyproject.toml?

Often yes, as long as it sticks to the supported subset. Files that use date values or multi-line strings will need those parts adjusted, since the parser flags them.

TOML to JSON Converter

Convert TOML to JSON in your browser

This tool parses TOML configuration and outputs clean, indented JSON — useful for feeding a TOML config into JavaScript code, an API, or any tooling that expects JSON. It targets the TOML constructs people actually paste, all processed locally.

How it works

The built-in parser implements a focused subset of TOML v1.0.0. It reads line by line, handling key = value pairs with basic and literal strings, integers and floats (including underscore separators), and booleans. [table] and [parent.child] headers create nested objects, dotted keys nest the same way, and [[array of tables]] headers append objects to a JSON array. Inline arrays of scalars and # line comments are supported. Constructs it deliberately does not implement — multi-line strings and date/time types — raise a clear error instead of being mis-parsed.

Example

This TOML:

title = "Gera Tools"
version = 6

[owner]
team = "platform"

[[servers]]
name = "eu-1"
port = 8080

becomes:

{
  "title": "Gera Tools",
  "version": 6,
  "owner": { "team": "platform" },
  "servers": [{ "name": "eu-1", "port": 8080 }]
}

Everything runs locally in your browser — your config is never uploaded or stored.