What is TOML and why convert JSON to it?

TOML (Tom's Obvious, Minimal Language) is a config file format designed to be minimal and easy to read. It is widely used in Rust (Cargo.toml), Python (pyproject.toml), and Hugo. Converting JSON lets you use JSON-generated data in these tools.

Are there any JSON structures that cannot be expressed in TOML?

Arrays of mixed types (e.g. [1, "two", true]) and null values are not supported by TOML. The tool will flag these cases. Homogeneous arrays and nested objects convert cleanly.

How are nested JSON objects represented in TOML?

Nested objects become TOML sections with bracket notation. For example, {"db": {"host": "localhost"}} becomes [db] followed by host = "localhost".

How are JSON arrays of objects handled?

Arrays of objects become TOML array-of-tables notation using double brackets [[table]]. Each object in the array becomes a [[table]] entry.

Does this tool send my data to a server?

No. All conversion is performed entirely in the browser. Your data is never sent to any server.

Ctrl+K

JSON to TOML Conversion

Convert JSON data to TOML format. Useful for config files (e.g. Cargo.toml) and tool settings. Enter text or upload a file (up to 100KB) and see real-time conversion results.

JSON Input

TOML Output

Read Only

How to use

About this tool

Converts JSON strings to TOML.

How to use

Paste JSON; the TOML output can be copied.

Use cases

• Converting JSON to TOML for config files (e.g. Cargo.toml) • Tool config format conversion • Readability

Code Examples

JSON input example (before)

Read Only

1{
2  "package": {
3    "name": "my-app",
4    "version": "1.0.0"
5  },
6  "database": {
7    "host": "localhost",
8    "port": 5432,
9    "enabled": true
10  }
11}

TOML output example (after)

Read Only

1[package]
2name = "my-app"
3version = "1.0.0"
4
5[database]
6host = "localhost"
7port = 5432
8enabled = true
9

How it works

■ What is JSON? JSON (JavaScript Object Notation) represents key-value pairs, arrays, and nested objects as text. Commonly used for API requests/responses and data exchange. ■ What is TOML? TOML (Tom's Obvious, Minimal Language) is a human-readable format for config files. It supports key=value pairs, [sections], arrays, dates, integers, floats, and booleans. Widely used in Rust (Cargo.toml), Python (pyproject.toml), and elsewhere. ■ How conversion works The tool parses the JSON into an object and serializes it to TOML. All processing runs in the browser.

FAQ

Q: What is TOML and why convert JSON to it?: A: TOML (Tom's Obvious, Minimal Language) is a config file format designed to be minimal and easy to read. It is widely used in Rust (Cargo.toml), Python (pyproject.toml), and Hugo. Converting JSON lets you use JSON-generated data in these tools.
Q: Are there any JSON structures that cannot be expressed in TOML?: A: Arrays of mixed types (e.g. [1, "two", true]) and null values are not supported by TOML. The tool will flag these cases. Homogeneous arrays and nested objects convert cleanly.
Q: How are nested JSON objects represented in TOML?: A: Nested objects become TOML sections with bracket notation. For example, {"db": {"host": "localhost"}} becomes [db] followed by host = "localhost".
Q: How are JSON arrays of objects handled?: A: Arrays of objects become TOML array-of-tables notation using double brackets [[table]]. Each object in the array becomes a [[table]] entry.
Q: Does this tool send my data to a server?: A: No. All conversion is performed entirely in the browser. Your data is never sent to any server.