TOML ↔ JSON Converter

What Is TOML to JSON Conversion?

TOML (Tom's Obvious, Minimal Language) is a configuration file format widely used in Rust (Cargo.toml), Python (pyproject.toml), and many other ecosystems. This TOML to JSON converter lets you convert TOML configuration files to JSON and convert JSON back to TOML — all in your browser without uploading any data. It is useful for debugging configuration, migrating between formats, or integrating TOML-based configs with JSON-based tooling.

How to Use TOML ↔ JSON Converter

1. Select the conversion direction: TOML → JSON or JSON → TOML.
2. Paste your input into the left panel, or click Load Sample.
3. Click Convert to run the conversion.
4. The result appears in the right panel. Click Copy to copy it.
5. Use the ⇄ Swap button to flip the direction and use the output as new input.

Features

• Bidirectional — convert TOML to JSON and JSON to TOML
• Configurable JSON indent — 2 or 4 spaces
• Swap button — flip direction and reuse output as input
• Clear error messages — parse errors shown inline
• Privacy-first — all processing is local, nothing is uploaded

FAQ

What is TOML?

TOML (Tom's Obvious, Minimal Language) is a configuration file format designed to be easy to read. It is used by Rust's Cargo.toml, Python's pyproject.toml, and many other tools as a human-friendly alternative to JSON or YAML for configuration.

Can all TOML files be converted to JSON?

Most TOML files convert cleanly to JSON. TOML dates and times are converted to ISO 8601 strings. TOML comments are not preserved in JSON since JSON does not support comments.

Can all JSON files be converted to TOML?

JSON files with string, number, boolean, array, and object values convert to TOML. JSON null values are not supported in TOML and will cause a conversion error.

Is my data sent to a server?

No. All conversion runs entirely in your browser. No data is sent to any server.