Convert TOML to JSON Online Parse TOML configuration files and convert to JSON format.

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TOML to JSON

Parse TOML configuration files and convert to JSON format.

Paste TOML

Paste your TOML configuration into the input field.

View JSON

The parsed JSON output appears with proper formatting.

Copy result

Copy the JSON for use in applications and APIs.

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What Is TOML to JSON?

TOML to JSON converts Tom's Obvious Minimal Language configuration files into JavaScript Object Notation format. TOML is a popular configuration format used by Cargo (Rust), pyproject.toml (Python), Hugo, and many other tools. This converter parses TOML tables, array-of-tables, inline arrays, strings, numbers, booleans, and comments, producing a clean JSON representation. It handles section headers, dotted keys, and nested structures.

Why Use TOML to JSON?

Parses standard TOML features: tables, array-of-tables, inline arrays.
Handles strings, numbers, booleans, and comments.
Clean JSON output with 2-space indentation.
No server upload — parsing happens in your browser.

Common Use Cases

Rust Development

Parse Cargo.toml files to understand project dependencies and configuration.

Python Projects

Convert pyproject.toml to JSON for programmatic access to project metadata.

Configuration Analysis

Transform TOML config files to JSON for processing with JavaScript tools.

Migration

Convert TOML configuration to JSON when migrating to applications that use JSON config.

Technical Guide

The parser processes TOML input line by line. Comments (starting with #) are stripped before processing. The parser maintains a "current table" pointer that starts at the root object.

[table] headers create nested objects in the JSON structure, with dotted names creating nested levels. [[array-of-tables]] headers create or append to arrays of objects. Key-value pairs are parsed and added to the current table.

Value parsing supports: double-quoted strings (with escape sequences), single-quoted literal strings, integers, floating-point numbers, booleans (true/false), and inline arrays. Inline arrays can contain mixed types.

Limitations: This implementation covers the most common TOML features but may not handle every edge case in the full TOML specification. Inline tables, multi-line strings, and datetime types have limited support.

Tips & Best Practices

1
Comments in TOML are stripped during parsing — they are not represented in JSON.
2
Table headers [section] create nested objects in the JSON output.
3
Array-of-tables [[section]] create arrays of objects.
4
For complex TOML files, validate the JSON output to ensure all values parsed correctly.

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Frequently Asked Questions

Q Does it handle all TOML features?

It supports the most common features: tables, array-of-tables, strings, numbers, booleans, inline arrays, and comments. Some advanced features may have limited support.

Q Are TOML comments preserved?

No, JSON does not support comments, so TOML comments are discarded during conversion.

Q How are datetime values handled?

TOML datetime values are output as strings in the JSON. Native TOML datetime parsing has limited support.

Q What about multi-line strings?

Multi-line basic strings (""") have basic support. Multi-line literal strings (''') may need to be converted to single-line first.

Q Is it fully TOML compliant?

It covers the most common TOML patterns. For full TOML 1.0 compliance, consider using a dedicated TOML parsing library.

About This Tool

TOML to JSON is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.