What is TOML used for?

TOML (Tom's Obvious Minimal Language) is a configuration file format used by Rust (Cargo.toml), Python (pyproject.toml), and many other tools. It's designed to be easy to read and write.

Can I convert JSON to TOML?

Yes! The tool supports bidirectional conversion. Switch to "JSON to TOML" mode to convert JSON objects into TOML format.

Does TOML support comments?

Yes, TOML supports comments using the # symbol. However, comments are not preserved when converting to JSON and back.

TOML Formatter - Format and Convert TOML to JSON Online Free

How to Use the TOML Formatter

Paste your TOML content into the input field. The tool will automatically parse and validate your TOML, showing any errors. Use the conversion buttons to switch between TOML and JSON formats, or use the Format TOML mode to beautify your configuration files.

Features

TOML to JSON - Convert TOML configuration to JSON format
JSON to TOML - Convert JSON objects back to TOML
Format TOML - Beautify and standardize TOML formatting
Validation - Instant syntax error detection
Indentation Options - Choose 2 or 4 space indentation for JSON
Copy & Share - Copy results or share via URL

Works great with the JSON Formatter for further JSON processing and YAML Converter for YAML workflows.

What is TOML?

TOML (Tom's Obvious Minimal Language) is a configuration file format that aims to be easy to read due to its clear semantics. It was created by Tom Preston-Werner, co-founder of GitHub.

Key TOML Features

Human-readable - Clear, intuitive syntax
Typed values - Strings, integers, floats, booleans, dates
Tables - Nested structures using [section] headers
Arrays - Both inline and table arrays supported
Comments - Single-line comments with #

TOML vs YAML vs JSON

Each format has its strengths:

TOML - Best for configuration files, explicit and unambiguous
YAML - Good for complex nested data, but whitespace-sensitive
JSON - Universal data interchange, strict syntax

TOML is often preferred for application configuration because it's less error-prone than YAML (no whitespace sensitivity) and more readable than JSON (supports comments).

Common TOML Files

Cargo.toml - Rust package manifest
pyproject.toml - Python project configuration (PEP 518)
config.toml - Application settings
netlify.toml - Netlify deployment configuration
hugo.toml - Hugo static site generator config

TOML Syntax Quick Reference

# This is a comment
title = "My App"
version = "1.0.0"

[database]
host = "localhost"
port = 5432
enabled = true

[servers.alpha]
ip = "10.0.0.1"

[[products]]
name = "Hammer"
price = 9.99

[[products]]
name = "Nail"
price = 0.05

Frequently Asked Questions

Is my TOML data secure?

Yes! All TOML processing happens entirely in your browser using JavaScript. Your configuration files are never uploaded to any server.

Why are comments lost during conversion?

JSON does not support comments, so when converting TOML to JSON, comments are discarded. Converting back to TOML will not restore them.

Can I format Cargo.toml files?

Yes! This formatter works with any valid TOML file, including Cargo.toml for Rust projects. It will validate the syntax and help you identify any errors.

What TOML version is supported?

The formatter supports TOML 1.0, including all standard features like inline tables, arrays of tables, and datetime values.

TOML Formatter