JSON to TOML Converter — Free Online JSON to TOML Tool

JSON to TOML Converter — Free Online JSON to TOML Tool. Free online JSON to TOML converter. Paste any JSON object to instantly convert it to TOML configuration format — ideal for Rust Cargo.toml, Hugo config, and more. All processed in your browser.

Instantly convert JSON to TOML with our free online JSON to TOML converter.

Paste any JSON object and get clean, correctly formatted TOML output — perfect for Rust Cargo.toml, Hugo site config, Python pyproject.toml, and any configuration file that requires TOML format.

Whether you are a developer translating API responses, a DevOps engineer standardizing config files, or a systems programmer migrating settings, our tool makes it easy to convert JSON to TOML online in seconds.

Supports nested objects, arrays, strings, numbers, and booleans. Our JSON to TOML tool supports JSON5 syntax (trailing commas, comments) and runs entirely in your browser — your configuration data and secrets never leave your device.

Try our TOML to JSON Converter to reverse the process, JSON to YAML Converter for another config format, or JSON Prettify to format your JSON before converting.

Frequently asked questions

How do I convert JSON to TOML?

Paste your JSON into JSON input or click Load sample. TOML output updates as you type: simple values become key = value lines, nested objects become [section] tables and arrays of objects become [[array]] tables. Copy the result with the copy button.

Why is the TOML output empty?

A TOML document is always a table, so the top level of your JSON must be an object. A top-level array or single value cannot be converted and gives no output. Invalid JSON shows Provided JSON is not valid.

What happens to null values?

TOML has no null type, so keys whose value is null are left out of the output, and null items inside arrays are removed.

Why do large numbers contain underscores?

Integers with four or more digits are written with underscores as thousands separators, for example 12_840. This is valid TOML, and parsers read it as the plain number 12840.

Can I paste JSON with comments?

Yes. The input is parsed as JSON5, so comments, trailing commas, single quotes and unquoted keys are accepted. Comments are not carried over to the TOML.

How to use this online tool

JSON to TOML Converter — Free Online JSON to TOML Tool is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

JSON to TOML Converter — Free Online JSON to TOML Tool keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use JSON to TOML Converter — Free Online JSON to TOML Tool for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.