Does this send my document anywhere?

No. Formatting runs entirely in your browser.

Does formatting change the data?

No. Parsing and re-serializing preserves the same keys and values; only whitespace, quoting, and key formatting are normalized.

Does it preserve the order of keys and tables?

In the common case, yes. The document is parsed into a plain object and re-serialized in the same order the keys were encountered, since JavaScript objects preserve insertion order for string keys.

What TOML types does it support?

The full core spec: strings, integers, floats, booleans, dates and times, arrays, and both inline and standard tables, since it's built on smol-toml, a spec-compliant parser.

TOML Formatter - Format TOML Online

Overview

Introduction

TOML config files hand-edited over time often end up with inconsistent spacing and quoting.

This tool parses your TOML and re-serializes it, producing a normalized document, entirely in your browser.

What Is TOML Formatter?

A TOML formatter that parses input into structured data and re-serializes it with consistent formatting, the same parse-then-print approach a JSON formatter uses.

Comments are not preserved, since TOML's data model doesn't carry them through a parse round-trip.

How TOML Formatter Works

The document is parsed into a table structure, then re-serialized with normalized key and value formatting.

A malformed document (a missing quote, for example) fails to parse and reports the exact line and column.

When To Use TOML Formatter

Use it when cleaning up a hand-edited config file so key/value spacing and quoting are consistent.

It's also a fast way to verify that a TOML document is syntactically valid before using it in a build or CI pipeline.

Often used alongside JSON Formatter & Beautifier and YAML Formatter & Prettifier.

Features

Advantages

Runs entirely client-side.
Round-trips through a real parser, so output is guaranteed valid TOML if the input was valid.
Supports the full TOML spec, including dates/times and inline tables, via a dedicated spec-compliant parser.

Limitations

Comments in the original document are not preserved, since they aren't part of TOML's parsed data model.

Examples

Inconsistent spacing

Input

name="app"
version  =  "1.0.0"

Output

name = "app"
version = "1.0.0"

Spacing around the equals sign is normalized to a single space on each side.

Best Practices & Notes

Best Practices

Format config files before committing them so diffs reflect real value changes.
Keep a copy of a heavily commented config file before formatting it, since comments don't survive the round-trip.

Developer Notes

Uses `smol-toml`'s `parse()`/`stringify()` pair, a lightweight, spec-compliant TOML implementation with no native dependencies.

TOML Formatter Use Cases

Cleaning up a hand-edited Cargo.toml or pyproject.toml snippet
Validating a TOML document parses before using it in a build
Checking that a TOML snippet from documentation is syntactically valid before adding it to a project

Common Mistakes

Expecting comments to survive formatting; they're dropped because TOML's parsed data model doesn't retain them.
Relying on this tool to validate against a schema; it only confirms the document parses as valid TOML, not that specific keys or types are present.

Tips

If you need to keep comments, edit the file directly instead of round-tripping it through this tool.
Use the reported line and column from a failed parse to jump straight to the problem in a hand-edited config file.

TOML Formatter