JSON to TOML Converter
Convert JSON data to TOML online. Paste JSON and the corresponding TOML configuration text appears instantly, suited to writing and migrating files such as Rust's Cargo.toml and Python's pyproject.toml.
FreeOnline Tool
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How to Use
- Paste or edit your JSON in the input box
- The converted TOML appears below in real time
- If the JSON is malformed, a specific parse error is displayed
Features
- Converts JSON objects, arrays and nested structures into equivalent TOML
- Converts as you type, with no manual trigger
- Reports a clear parse error when the JSON is invalid
Use Cases
Writing Rust Cargo.toml configuration
Work out dependencies and configuration structure in JSON, then convert in one step and paste the result into Cargo.toml.
Writing Python pyproject.toml configuration
Convert project configuration expressed as JSON into the TOML that pyproject.toml expects.
Migrating configuration formats
Convert content quickly when a project moves from JSON configuration to TOML.
Learning TOML syntax
Compare JSON input against the converted TOML to pick up how TOML expresses tables and arrays.
FAQ
Which JSON data types are supported?
Objects, arrays, strings, numbers and booleans, along with nested structures. TOML has no direct equivalent for null, so those values are handled according to TOML conventions during conversion.
Why am I seeing a JSON parse error?
The input is not valid JSON. Check that brackets, quotes and commas all match, and read the error message for the specific problem.
Can I paste the TOML straight into Cargo.toml?
The output is standard TOML syntax and can be used directly, but check the required fields against the conventions of your specific tool, such as Cargo or Poetry, before relying on it.
Is my data uploaded to a server?
No. Conversion runs entirely in your browser and nothing is transmitted.