How are TOML tables, inline tables, and arrays of tables mapped to JSON?

Standard TOML tables [table] become JSON objects, inline tables { a = 1 } become nested JSON keys, and arrays of tables [[items]] map directly to JSON arrays of objects.

Why does TOML conversion fail when converting an array?

TOML requires the root element of a document to be a key-value table (map), not a top-level array. Wrap top-level arrays in a parent key before converting to TOML.

ConvertHubPRO / FREE

Top Leaderboard

728 × 90 px • CLS-Locked

Developer Tools•Free & Instant

TOML to JSON / YAML Converter

Parse Cargo.toml, pyproject.toml, and TOML configs into JSON and YAML structures.

Instant browser processing Private & Auto-Purged

100% Client-Side Privacy GuaranteedZero Cloud Latency

Your data is computed entirely inside your browser's JavaScript engine and is never transmitted across the network.

Load Sample Preset:

Indent:

TOML Input Code

toml

16 lines • 396 chars

JSON Converted Output

json

33 lines•591 chars•591 B

1{
2  "package": {
3    "name": "converthub-core",
4    "version": "0.2.1",
5    "edition": "2021",
6    "authors": [
7      "ConvertHub Team <dev@converthub.com>"
8    ],
9    "description": "High performance client-side media and data conversion engine"
10  },
11  "dependencies": {
12    "serde": {
13      "version": "1.0",
14      "features": [
15        "derive"
16      ]
17    },
18    "serde_json": "1.0",
19    "tokio": {
20      "version": "1.35",
21      "features": [
22        "full"
23      ]
24    }
25  },
26  "profile": {
27    "release": {
28      "opt-level": 3,
29      "lto": true,
30      "codegen-units": 1
31    }
32  }
33}

In-Content Native Banner

728 × 90 px • CLS-Locked

How to Convert with TOML to JSON / YAML Converter

Follow these 3 simple steps to complete your conversion in seconds.

Step 1 of 3

Paste or Upload Source Data

Paste your TOML to JSON / YAML code directly into the left editor pane or click Upload to select a file.

💡 Tip: 100% client-side execution in your browser memory. Zero server uploads.

Step 2 of 3

Configure Syntax & Dialect Options

Adjust indentation (2 or 4 spaces), toggle alphabetical key sorting, set SQL table name and dialect quotes, or pick a built-in template.

Step 3 of 3

Instant Result & Copy / Download

View formatted output in real time with line numbers and syntax highlighting. Click Copy or Download to save.

TOML to JSON / YAML Converter Serialization & AST Mapping Specification

Formula representation used for accurate calculations:

Native JavaScript AST = Parser.load(Input Source Stream) Target Output = Serializer.dump(AST, { indent, sortKeys, dialect })

Calculation Example: Strict Type Preservations: YAML & TOML Maps ↔ JSON Objects | Sequences ↔ JSON Arrays | Timestamps ↔ ISO-8601 Strings | Nulls ↔ null

Structured Data Types Mapping Matrix

Quick reference lookup table for standard unit calculations.

Standard type equivalencies across JSON, YAML, and TOML serialization formats.
Data Type / Construct	JSON Representation	YAML / TOML Representation
Key-Value Map	{ "key": "value" }	key: value / key = "value"
Array / List	[1, 2, 3]	- 1\n- 2 / [1, 2, 3]
Boolean	true / false	true / false
Null / Nil	null	null / ~ (omitted in TOML)
Multiline String	"Line 1\nLine 2"	\| (Literal) / """ (Multiline)
Numbers / Floats	42 / 3.14159	42 / 3.14159

Frequently Asked Questions

Common questions and answers about TOML to JSON / YAML Converter.

Yes! ConvertHub includes a robust TOML v1.0.0 parser (smol-toml) capable of parsing Rust Cargo.toml, Python pyproject.toml, and Go configuration files directly into structured JSON and YAML.