TOML to JSON Converter — Free Online TOML Parser

TOML is the configuration format of choice for Rust projects (Cargo.toml), Python tools (pyproject.toml), Hugo sites, Gitea, and many modern CLI applications. When you need to process TOML outside its native ecosystem, our free TOML to JSON converter parses TOML and outputs clean, valid JSON — entirely in your browser.

What Is TOML?

TOML (Tom’s Obvious Minimal Language) is a configuration file format created by Tom Preston-Werner (co-founder of GitHub) in 2013. TOML is designed to be minimal, readable, and map unambiguously to a hash table (dictionary). It prioritizes human-writability over machine-generatability.

TOML is the native configuration format for:

• Rust/Cargo — Every Rust project has a Cargo.toml for dependencies and metadata
• Python packaging — pyproject.toml is the modern Python project configuration standard (PEP 517/518)
• Hugo — Static site generator uses config.toml or hugo.toml
• Gitea/Forgejo — Git hosting platform configuration
• Zola — Static site generator
• Deno — JavaScript runtime configuration
• InfluxDB — Time-series database configuration
• Ansible — Some modern playbook configurations

TOML vs. JSON vs. YAML

How to Use the TOML to JSON Converter

1. Paste your TOML content into the input field
2. Click Convert to JSON
3. The JSON output appears, pretty-printed with 2-space indentation
4. Click Copy to grab the JSON

All TOML parsing runs in your browser using a JavaScript parser. Your configuration data is never transmitted.

Example

TOML Input (Cargo.toml style):

[package]
name = "my-app"
version = "1.0.0"
edition = "2021"
authors = ["Alice <alice@example.com>"]
description = "A fast, reliable application"

[dependencies]
serde = { version = "1.0", features = ["derive"] }
tokio = { version = "1.0", features = ["full"] }
reqwest = "0.11"

[profile.release]
opt-level = 3
lto = true
codegen-units = 1

[[bin]]
name = "my-app"
path = "src/main.rs"

JSON Output:

{
  "package": {
    "name": "my-app",
    "version": "1.0.0",
    "edition": "2021",
    "authors": ["Alice <alice@example.com>"],
    "description": "A fast, reliable application"
  },
  "dependencies": {
    "serde": { "version": "1.0", "features": ["derive"] },
    "tokio": { "version": "1.0", "features": ["full"] },
    "reqwest": "0.11"
  },
  "profile": {
    "release": {
      "opt-level": 3,
      "lto": true,
      "codegen-units": 1
    }
  },
  "bin": [
    {
      "name": "my-app",
      "path": "src/main.rs"
    }
  ]
}

TOML Data Types

TOML has native support for more data types than JSON:

Note: TOML datetime values are converted to strings in the JSON output, as JSON has no native datetime type.

Common Use Cases

Processing Cargo.toml programmatically — Parse Cargo.toml dependency lists in Python or JavaScript tools that analyze Rust project dependencies.

Migrating Hugo/Zola sites — Convert TOML-based site configurations to JSON for JavaScript-based build tooling.

API payload construction — Convert a developer-friendly TOML configuration file into JSON for posting to a REST API.

Cross-ecosystem tooling — Deserialize pyproject.toml or similar TOML configs in Node.js scripts for project automation.

Learning and documentation — Show TOML and its equivalent JSON structure side-by-side for educational documentation.

Frequently Asked Questions

Does TOML support comments?

Yes — TOML uses # for line comments, just like Python and TOML’s yaml counterparts. However, since JSON has no comment support, comments are stripped in the JSON output. The [[bin]] or [package] structure is preserved as objects/arrays in the JSON representation.

What is the difference between [table] and [[array of tables]]?

[section] defines a standard TOML table (converts to a JSON object). [[section]] defines an array of tables — every occurrence of [[section]] creates a new entry in a JSON array. This is TOML’s way of representing a list of structured items.

Does this handle nested TOML sections?

Yes. Dotted keys like [server.database] or a.b.c = "value" create nested JSON objects: {"server": {"database": {...}}}. Our parser handles standard dot-separated section nesting.

Can I use this for pyproject.toml?

Yes. pyproject.toml follows standard TOML syntax. Paste the contents and the converter will produce the corresponding JSON representation of your Python project configuration.

Why is TOML popular for Rust projects?

Rust’s package manager (Cargo) chose TOML from the start because of its clarity and strictness. TOML’s unambiguous mapping to data structures makes it easy to parse and validate. The format explicitly avoids YAML’s footguns (significant indentation, implicit types, multiple ways to express the same thing).

Is there a JSON to TOML converter?

Not on this page, but you can use our JSON Formatter to clean up JSON. For JSON to TOML conversion, dedicated libraries exist: toml in Rust, tomli_w in Python, and npm packages like json-to-toml in Node.js.