Free TOML ↔ JSON Converter Online — Uttir
Uttir

TOML ↔ JSON Converter

Convert TOML to JSON and JSON to TOML, instantly in your browser. Useful for pyproject.toml, Cargo.toml, and any modern config file. Free, no upload.

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TOML ↔ JSON Converter — TOML (Tom's Obvious Minimal Language) is the configuration format you will find in pyproject.toml, Cargo.toml, and many other modern config files. It is designed to be easy to read and unambiguous — there is exactly one way to write any value.

Conversion runs locally in your browser. Your config never leaves the page.

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What is toml ↔ json converter?

TOML (Tom's Obvious Minimal Language) is the configuration format you will find in pyproject.toml, Cargo.toml, and many other modern config files. It is designed to be easy to read and unambiguous — there is exactly one way to write any value.

This tool converts between TOML and JSON in both directions. JSON-to-TOML is useful when you have data in code and want a clean config file. TOML-to-JSON is useful when you want to inspect a TOML file as a tree, or feed it into a script that only accepts JSON.

How to use it

  1. Choose direction

    Toggle between TOML → JSON and JSON → TOML.

  2. Paste your input

    The output updates as you type. JSON-to-TOML expects a JSON object (or array) at the top level.

  3. Copy or download

    Use Copy to grab the converted text, or Download to save as a file.

Examples

pyproject.toml to JSON

A minimal Python project config.

[project]
name = "uttir"
version = "0.1.0"

[project.dependencies]
python = "^3.11"

Result: { "project": { "name": "uttir", "version": "0.1.0", "dependencies": { "python": "^3.11" } } }

JSON to TOML

A small config object emitted as TOML.

{"name": "uttir", "version": "0.1.0", "private": true}

Result: name = "uttir" version = "0.1.0" private = true

Frequently asked questions

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Last reviewed: 2026-08-26