JSON to TOML Converter
Convert JSON objects to TOML (Tom's Obvious, Minimal Language) format. Perfect for configuration files in Rust, Python, and Go projects with automatic table and array formatting.
Conversion Options
TOML doesn't support nulls
Recommended Settings
TOML Best Practices
- •Use TOML for configuration files - more readable than JSON
- •Group related settings in tables [section]
- •Use array of tables [[array]] for repeated config blocks
- •TOML does not support null values - design configs without nulls
- •Comments with # make configs self-documenting
When JSON Works Better
- •APIs and data transfer (JSON is standard for HTTP)
- •Dynamic data with nulls or undefined values
- •Deeply nested hierarchical data structures
- •When you need strict schema validation
- •JavaScript/browser environments (native JSON support)
Pro Tips
- •TOML is the standard for Rust (Cargo.toml), Python (pyproject.toml), and many Go tools
- •Arrays of objects become array of tables: [[servers]] for multiple server configs
- •Nested objects become dotted tables: [database.connection] for database → connection
- •All conversion happens client-side for privacy and security
Most Popular
Skip nulls enabled with blank lines between sections for readability
When to Use This Tool
Convert JSON configs to Cargo.toml format for Rust projects. TOML is Rust's standard for package manifests, dependencies, and build configurations with readable syntax.
Generate pyproject.toml for Python projects using Poetry or modern packaging. TOML has replaced setup.py as the standard for Python project configuration and dependencies.
Convert JSON configs to TOML for better readability and maintainability. TOML's clear syntax makes it ideal for human-edited configuration files that need to be version controlled.
Use TOML for container orchestration configs in tools that support it. TOML provides cleaner syntax than YAML for defining services, networks, and volumes.
Convert JSON configs to TOML for tools like Netlify, Vercel, or custom build systems. TOML's readability makes pipeline configs easier to review and maintain.
Migrate legacy JSON configs to TOML when switching to tools that prefer TOML. Modern dev tools increasingly favor TOML for its balance of simplicity and features.
How It Works
Paste JSON into the input field
Tool validates JSON syntax
Check for null values (TOML limitation)
Convert JSON objects to TOML tables
Convert nested objects to dotted tables
Convert arrays of objects to array of tables
Apply formatting options (spacing, sorting)
Copy to clipboard or download as .toml file
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Pure JavaScript for optimal performance on modern browsers.
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Frequently Asked Questions
What is TOML and why use it over JSON?
TOML (Tom's Obvious, Minimal Language) is designed specifically for configuration files. It's more readable than JSON for humans, supports comments, and has cleaner syntax for nested configs. Rust, Python, and many modern tools use TOML as their standard config format.
What happens to null values in JSON?
TOML does not support null values at all - it's a fundamental limitation of the format. The converter automatically skips null values with the 'Skip null values' option enabled. If you need nulls, consider using JSON, YAML, or redesigning your config without nulls.
How are JSON objects converted to TOML?
JSON objects become TOML tables with [section] headers. Nested objects become nested tables like [database.connection]. Each key-value pair in the object becomes a TOML key-value pair under its table header.
How do I convert arrays of objects?
Arrays of objects become TOML array of tables using [[array]] syntax. Each object in the array gets its own [[array]] header. For example, an array of server configs becomes [[servers]] repeated for each server.
Can I convert JSON arrays at the root level?
No, TOML requires the root to be a table (object), not an array. If your JSON has a root-level array, wrap it in an object first: {"items": [...]}. This is a TOML specification requirement.
What's the difference between tables and inline tables?
Tables use [section] headers and span multiple lines, good for readable configs. Inline tables use {key = value} on one line, useful for simple grouped data. The converter generates standard tables for better readability.
How do I use the generated TOML file?
Download the .toml file and use it in your project. For Rust: Cargo.toml for dependencies. For Python: pyproject.toml for Poetry/pip. Most languages have TOML parsers: Rust (toml crate), Python (tomli/tomllib), JavaScript (toml npm package).
Are my files secure during conversion?
Yes, absolutely! All conversion happens entirely in your browser using client-side JavaScript. Your JSON data never leaves your computer or gets sent to any server. The tool works completely offline after the page loads.