Free Toolkit

JSON to TOMLConvert JSON objects to TOML configuration format with tables and array tables.

JSON to TOML illustration
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JSON to TOML

Convert JSON objects to TOML configuration format with tables and array tables.

How to Use
1

Paste JSON

Paste a JSON object into the input field.

2

View TOML

TOML output with tables and proper formatting appears instantly.

3

Use in config

Copy the TOML for use in Rust, Python, or other configuration files.

What Is JSON to TOML?

JSON to TOML converts JavaScript Object Notation into Tom's Obvious Minimal Language format. TOML is designed for configuration files and is used by Rust (Cargo.toml), Python (pyproject.toml), and many other tools. This converter maps JSON objects to TOML tables, JSON arrays of objects to TOML array-of-tables (double brackets), and primitive values to their TOML equivalents. The output produces clean, human-readable configuration that follows TOML conventions.

Why Use Our JSON to TOML?

  • Proper TOML structure with [tables] and [[array-of-tables]] notation.
  • Handles strings, numbers, booleans, arrays, and nested objects.
  • Clean output following TOML style conventions.
  • No dependencies — pure JavaScript TOML generation.

Common Use Cases

Rust Development

Generate Cargo.toml configuration from JSON data.

Python Projects

Create pyproject.toml configuration from JSON specifications.

Configuration Management

Convert JSON config files to TOML for applications that prefer TOML format.

Hugo/Static Sites

Generate TOML front matter and configuration for Hugo and similar static site generators.

Technical Guide

The converter categorizes JSON values into three groups: simple values (strings, numbers, booleans, simple arrays) are output as inline key-value pairs, nested objects become TOML tables with [section] headers, and arrays of objects become TOML array-of-tables with [[section]] headers. Strings are quoted with double quotes and have backslashes and internal quotes escaped. Numbers and booleans are output as bare values. Simple arrays (containing only primitives) use TOML inline array syntax [value1, value2]. The converter processes simple values first, then tables, then array-of-tables, following TOML convention where bare keys appear before table headers. Nested tables use dotted key notation (e.g., [parent.child]). Note: TOML requires a root table (object) — non-object JSON root values are not supported.

Tips & Best Practices

  • 1
    The root JSON value must be an object — arrays and primitives cannot be TOML root values.
  • 2
    Arrays of objects become TOML array-of-tables ([[section]]) notation.
  • 3
    Deeply nested objects produce dotted table names (e.g., [parent.child.grandchild]).
  • 4
    Simple arrays (non-object items) use TOML inline array format.

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Frequently Asked Questions

QWhat JSON types map to TOML?
Objects → tables, arrays of objects → array-of-tables, strings/numbers/booleans → bare values, simple arrays → inline arrays.
QCan I convert back to JSON?
Yes, use our TOML to JSON converter for the reverse transformation.
QAre dates handled?
TOML has native date/time types, but JSON date strings are output as TOML strings. Manual editing may be needed for TOML datetime values.
QIs the output valid TOML?
Yes, for standard JSON structures. Edge cases with deeply mixed nesting may need manual adjustment.
QWhy does the root need to be an object?
TOML specification requires the root to be a table (key-value map). Arrays and primitives cannot be root values.

About JSON to TOML

JSON to TOML is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.