TOML Converter

Convert between TOML and JSON

TOML

JSON

How to use TOML Converter

  1. •Choose your conversion direction — TOML to JSON or JSON to TOML.
  2. •Paste your input into the editor. For TOML, this might be a Cargo.toml, pyproject.toml, or any valid TOML document. For JSON, paste any valid JSON object.
  3. •View the converted output in the output panel. The tool preserves the structure and data types of your input.
  4. •Copy the result for use in your project, documentation, or tooling.

What is TOML?

TOML stands for Tom's Obvious, Minimal Language. It is a configuration file format designed to be easy to read thanks to its clear semantics. Unlike JSON, TOML supports comments, multi-line strings, dates and times as first-class types, and a table syntax that avoids deeply nested braces.

A TOML file is organized into tables (denoted by [section] headers) and key-value pairs. Nested tables use dotted keys or [parent.child] notation. Arrays of tables use [[array_name]]. This structure maps naturally to the nested objects and arrays in JSON, which is why bidirectional conversion works well.

TOML has become the standard configuration format in several ecosystems. Rust uses Cargo.toml for package manifests. Python's modern packaging standards use pyproject.toml (PEP 518, PEP 621). Hugo, the static site generator, uses TOML for site configuration. InfluxDB, Deno, and many other tools have adopted it as well.

One key difference from JSON is that TOML preserves the distinction between integers and floats, supports datetime values natively, and allows inline tables for compact representations. When converting to JSON, datetimes become ISO 8601 strings and the integer/float distinction may be lost since JSON has only one number type.

Common use cases

  • •Rust developers: Quickly inspect the structure of a Cargo.toml as JSON for programmatic processing, or convert JSON output from a tool back into TOML format.
  • •Python packaging: Convert between pyproject.toml and JSON when working with tools that only accept one format.
  • •Configuration migration: Move a project from a JSON config to TOML (or vice versa) by converting the existing file as a starting point.
  • •Debugging: Visualize a complex TOML file as JSON to understand deeply nested table relationships more easily.

FAQ

Q: Are TOML comments preserved in the conversion? A: No. Comments are not part of the TOML data model and are lost when converting to JSON. If you convert back to TOML, you will need to re-add comments manually.

Q: Does the converter handle TOML datetime types? A: Yes. TOML datetime values are converted to ISO 8601 strings in JSON, since JSON has no native date type.

Q: Can I convert TOML arrays of tables? A: Yes. TOML [[array]] syntax converts to JSON arrays of objects, and the reverse also works.

Is my data safe?

Yes. This tool runs entirely in your browser. Your data is never sent to our servers.

How to use TOML Converter

  1. Choose your conversion direction — TOML to JSON or JSON to TOML.
  2. Paste your input into the editor. For TOML, this might be a Cargo.toml, pyproject.toml, or any valid TOML document. For JSON, paste any valid JSON object.
  3. View the converted output in the output panel. The tool preserves the structure and data types of your input.
  4. Copy the result for use in your project, documentation, or tooling.

What is TOML?

TOML stands for Tom's Obvious, Minimal Language. It is a configuration file format designed to be easy to read thanks to its clear semantics. Unlike JSON, TOML supports comments, multi-line strings, dates and times as first-class types, and a table syntax that avoids deeply nested braces.

A TOML file is organized into tables (denoted by [section] headers) and key-value pairs. Nested tables use dotted keys or [parent.child] notation. Arrays of tables use [[array_name]]. This structure maps naturally to the nested objects and arrays in JSON, which is why bidirectional conversion works well.

TOML has become the standard configuration format in several ecosystems. Rust uses Cargo.toml for package manifests. Python's modern packaging standards use pyproject.toml (PEP 518, PEP 621). Hugo, the static site generator, uses TOML for site configuration. InfluxDB, Deno, and many other tools have adopted it as well.

One key difference from JSON is that TOML preserves the distinction between integers and floats, supports datetime values natively, and allows inline tables for compact representations. When converting to JSON, datetimes become ISO 8601 strings and the integer/float distinction may be lost since JSON has only one number type.

Common use cases

  • Rust developers: Quickly inspect the structure of a Cargo.toml as JSON for programmatic processing, or convert JSON output from a tool back into TOML format.
  • Python packaging: Convert between pyproject.toml and JSON when working with tools that only accept one format.
  • Configuration migration: Move a project from a JSON config to TOML (or vice versa) by converting the existing file as a starting point.
  • Debugging: Visualize a complex TOML file as JSON to understand deeply nested table relationships more easily.

FAQ

Q: Are TOML comments preserved in the conversion? A: No. Comments are not part of the TOML data model and are lost when converting to JSON. If you convert back to TOML, you will need to re-add comments manually.

Q: Does the converter handle TOML datetime types? A: Yes. TOML datetime values are converted to ISO 8601 strings in JSON, since JSON has no native date type.

Q: Can I convert TOML arrays of tables? A: Yes. TOML [[array]] syntax converts to JSON arrays of objects, and the reverse also works.

Is my data safe?

Yes. This tool runs entirely in your browser. Your data is never sent to our servers.