JSON to TOML: Convert JSON to TOML for Rust, Python & Go

What is TOML?

TOML (Tom's Obvious Minimal Language) is a configuration file format designed to be human-readable and unambiguous. It is the primary config format for Rust (Cargo.toml), Python (pyproject.toml), and Hugo static sites.

JSON vs TOML: Key Differences

• Comments: TOML supports # hash comments; JSON does not
• Dates: TOML has a native datetime type; JSON uses strings
• Readability: TOML uses flat dot-notation sections; JSON uses nested braces
• Use case: JSON for APIs and data; TOML for configuration files

When to Use JSON to TOML Conversion

• Migrating a Node.js package.json config to pyproject.toml
• Building a Rust package and needing to write Cargo.toml from JSON specs
• Converting Hugo or Zola site configuration between formats

// JSON Input
{
  "package": {
    "name": "my-lib",
    "version": "0.1.0",
    "authors": ["Alice <alice@example.com>"],
    "edition": "2021"
  },
  "dependencies": {
    "serde": { "version": "1.0", "features": ["derive"] }
  }
}

# TOML Output (Cargo.toml style)
[package]
name = "my-lib"
version = "0.1.0"
authors = ["Alice <alice@example.com>"]
edition = "2021"

[dependencies.serde]
version = "1.0"
features = ["derive"]