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

Why I Switched to TOML (Mostly)

YAML indentation bugs cost me a Friday night once. A single misplaced space broke a Kubernetes deployment. That's when I started reaching for TOML whenever I could. It's explicit, it supports comments (unlike JSON), and you can't accidentally break it with whitespace. This formatter helps me validate TOML files and convert between TOML and JSON when I need to.

What This Tool Does

TOML to JSON - When your API wants JSON but your config is TOML
JSON to TOML - Convert those JSON configs to something more readable
Format TOML - Standardize formatting across your team
Validation - Catch syntax errors before deployment
Indentation Options - 2 or 4 spaces for JSON output
Copy & Share - Quick sharing with colleagues

I pair this with the JSON Formatter for further processing and the YAML Converter when I'm stuck in YAML-land.

Why I Like TOML

TOML (Tom's Obvious Minimal Language) was created by Tom Preston-Werner, GitHub's co-founder. After dealing with YAML gotchas for years, I appreciate TOML's straightforward approach:

What Makes TOML Nice to Work With

Human-readable - No squinting at indentation levels
Typed values - Strings, integers, floats, booleans, dates - all explicit
Tables - Clean nested structures using [section] headers
Arrays - Both inline and table arrays, whichever fits better
Comments - Because sometimes you need to explain why

My Take on TOML vs YAML vs JSON

I use all three, but for different things:

TOML - My default for config files. Explicit, no indentation surprises
YAML - When the ecosystem demands it (Kubernetes, GitHub Actions). I'm careful with indentation
JSON - API payloads, package.json, anywhere machines need to read it

TOML wins for application config because you can't accidentally break it with a space, and you can add comments to explain non-obvious settings.

TOML Files I Work With Regularly

Cargo.toml - Rust projects (the format's biggest adopter)
pyproject.toml - Python projects with modern tooling
config.toml - Application settings I need to document
netlify.toml - Deployment configs
hugo.toml - Static site configs

TOML Syntax I 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. Everything processes in your browser - I don't see your config files, and they never leave your device. Privacy was a core requirement when I built this.

Why are comments lost during conversion?

JSON doesn't support comments (one of its biggest limitations, in my opinion). When you convert TOML to JSON, comments have nowhere to go. If you need them, keep a TOML version as your source of truth.

Can I format Cargo.toml files?

Absolutely! I use this for Rust projects all the time. Paste your Cargo.toml, validate the syntax, catch any errors before cargo gets upset.

What TOML version is supported?

TOML 1.0, the stable spec. All the standard features work - inline tables, arrays of tables, datetime values, the works.

TOML Formatter