TOML Editor — Validate & Format

Free online TOML editor with real-time syntax validation, formatting, minification, and conversion between TOML and JSON. No signup required.

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Powerful Features

Syntax Validation

Real-time TOML syntax checking with precise line-number error reporting. Instantly catches missing brackets, invalid keys, malformed dates, and structure problems.

Format & Prettify

Automatically reformat messy TOML with consistent indentation, sorted keys, and clean table headers. Makes configs readable and maintainable in one click.

TOML ↔ JSON Conversion

Convert TOML to JSON for API consumption or tooling, and JSON back to TOML for configuration. Handles nested tables, arrays, inline tables, and multiline strings.

Minify

Strip comments, blank lines, and unnecessary whitespace to produce the smallest valid TOML. Ideal for reducing config file sizes in production deployments.

TOML Sections & Syntax

Tables
[server]
host = "localhost"
port = 8080

[server.database]
engine = "postgresql"
max_connections = 100

[logging]
level = "info"
file = "/var/log/app.log"
Arrays
fruits = ["apple", "banana", "cherry"]

[[products]]
name = "Hammer"
sku = 738594937

[[products]]
name = "Nail"
sku = 284758393
color = "gray"

matrix = [
  [1, 2, 3],
  [4, 5, 6],
]
Inline Tables
point = { x = 1, y = 2 }

[server]
timeout = { connect = "5s", read = "30s" }

[database]
credentials = { user = "admin", pass = "secret" }
Dotted Keys
server.host.name = "localhost"
server.host.port = 8080

database.primary.url = "postgres://db1"
database.replica.url = "postgres://db2"

physical.color = "orange"
physical.shape = "round"
Multiline Strings
description = """
This is a multiline
basic string in TOML.
It preserves newlines.
"""

regex = '''\d{4}-\d{2}-\d{2}'''

path = '''C:\Users\dev\project'''

poetry = """
Roses are red
Violets are blue
TOML is awesome
And so are you
"""
Dates & Values
odate = 2024-01-15
otime = 12:30:00
odt1 = 2024-01-15T12:30:00Z
odt2 = 2024-01-15T12:30:00+08:00
odt3 = 2024-01-15T12:30:00-05:00

int_val = 42
float_val = 3.14
bool_val = true
hex_val = 0xDEADBEEF
oct_val = 0o755
bin_val = 0b11010110
inf_val = inf
nan_val = nan

Frequently Asked

What is TOML and when should I use it?
TOML (Tom's Obvious Minimal Language) is a configuration file format designed for readability and unambiguous parsing. Use it for application configs (Cargo.toml, pyproject.toml), CI/CD pipelines, and any scenario where human-editable configuration matters. It's simpler than YAML and more readable than JSON for config files.
How does the TOML validator work?
The validator parses your TOML using a spec-compliant parser in your browser — no data is sent to any server. It checks for syntax errors, invalid key names, malformed values, duplicate keys, and structural issues. Errors are reported with exact line numbers so you can fix them quickly.
Is my data private when using this editor?
Yes, completely. All parsing, validation, and conversion runs 100% in your browser using client-side JavaScript. No TOML or JSON data is ever transmitted to any server. You can even use this tool offline once the page has loaded.

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