About JSON to TOML
This tool converts JSON into TOML, the configuration format used by Rust (Cargo), Python (pyproject) and many other tools. Nested objects become tables, arrays of objects become arrays of tables, and values are typed and quoted correctly. It runs in your browser.
How JSON to TOML works
How to use it
- Paste a JSON object.
- Copy the generated TOML.
How it works
Top-level scalar keys are written first, then nested objects become [table] sections and arrays of objects become [[array of tables]]. Strings are quoted and numbers, booleans and arrays are emitted in TOML form.
Common uses
- Convert JSON to TOML
- Create a Cargo or pyproject config
- Migrate config formats
- Generate a TOML file
- Turn settings JSON into TOML
- Prepare a config for a tool
- Convert nested config
- Learn TOML structure
Frequently asked questions
How do I convert JSON to TOML?
Paste a JSON object and copy the TOML.
Must the top level be an object?
Yes — TOML documents are key/value tables.
How are nested objects handled?
They become [table] sections.
How are arrays of objects handled?
They become [[array of tables]].
Is my JSON uploaded?
No — it converts in your browser.
Does it cover all TOML features?
It covers common cases; very advanced features may differ.
Is it free?
Yes — completely free with no sign-up.