TOML Formatter – Format & Validate TOML Online

Fast, privacy-first TOML formatter that runs entirely in your browser. No uploads, instant formatting, developer-focused.

Format and validate TOML config files in your browser. Perfect for Cargo.toml, pyproject.toml, and any TOML-based config. No uploads—runs entirely client-side.

Privacy-first: your TOML never leaves your device. No uploads, no server. 100% client-side.

Lightweight and fast. Format on paste, Ctrl+Enter shortcut, drag-drop .toml files. Format-on-paste can be toggled off for large files.

IndentationIndentation:

Paste Cargo.toml or pyproject.toml here.

[package] name = "my-app" version = "0.1.0"
Formatted TOML will appear here.

Online vs Local TOML Formatter — Which Should You Use?

An online TOML formatter like this one runs in your browser with no install. You get instant formatting for Cargo.toml, pyproject.toml, or any config—without sending data to a server. Browser tools keep your configs private and are ideal for quick fixes, sharing snippets, or validating before commit.

A local formatter (e.g. in your editor or CLI) is better when you want to format entire repos or enforce style on save. For single-file checks, sharing with teammates, or one-off cleanup, an online formatter is faster and requires no setup. This tool gives you the best of both: developer-focused output, optional minify and diff view, and shareable links—all in the browser.

Why Use This TOML Formatter?

This tool is built for developers who work with Cargo.toml, pyproject.toml, and other TOML configs. It runs entirely in your browser—no uploads, no backend, instant formatting. Compare with our JSON formatter, YAML formatter, and GraphQL formatter for a consistent, privacy-first formatter ecosystem.

Comparison vs Generic Formatters

Generic code formatters do not understand TOML syntax. This formatter uses the correct grammar for tables, inline tables, and key-value pairs, so you get valid output and clear errors. It stays lightweight with no heavy editors.

Privacy Advantage (Browser-Only)

Your TOML never leaves your device. Formatting and validation run locally—no server, no logs, no data transfer. Sensitive configs stay private.

Developer Use Cases

Use it to beautify Cargo.toml or pyproject.toml before commit, validate configs from logs, or minify output for embedding. Supports 2 or 4 space indentation, trailing newline, and compact/minify mode.

Why Format TOML?

Who Uses TOML?

TOML is widely used in Rust (Cargo.toml), Python (pyproject.toml), and many other ecosystems for config files. Developers working on Rust crates, Python packages, or tool configs benefit from a formatter to keep files readable and consistent across teams.

Common TOML Mistakes

  • Missing or mismatched quotes around strings
  • Invalid table syntax—use [section] or [[array of tables]]
  • Duplicate keys or table headers
  • Bracket mismatch in table headers
  • Inconsistent indentation in inline tables

Benefits of Formatting Configs

Formatted TOML is easier to read, diff in version control, and review in code. Consistent indentation and line breaks reduce merge conflicts and help catch typos. Use this tool to beautify Cargo.toml, pyproject.toml, or any TOML config before committing.

TOML Formatter vs Generic Formatters

Generic code formatters (e.g. for JSON or YAML) do not understand TOML syntax. A TOML-specific formatter uses the correct grammar for tables, inline tables, and key-value pairs, so you get valid output and clear errors. This tool is built for TOML only and stays lightweight in the browser.

Privacy Advantages of Browser Tools

This TOML formatter runs entirely in your browser. Your config files are never uploaded to a server—formatting and validation happen locally. That means sensitive paths, keys, or project details stay on your device. No account, no logs, no data transfer.

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Frequently Asked Questions

What is this TOML formatter for?

Use this tool to clean and standardize TOML config files like Cargo.toml, pyproject.toml, and other application configs. It fixes indentation, ordering, and spacing so files stay readable and consistent.

How does TOML validation work?

The formatter uses a TOML parser under the hood. If your TOML has syntax issues (like mismatched brackets or invalid values), you'll see an error message with a line hint instead of formatted output.

Does any of my TOML leave the browser?

No. Formatting and validation run entirely in your browser. Your config files are never uploaded, logged, or stored on any server. Client-side privacy only.

Can I control indentation?

Yes. You can choose 2 or 4 spaces so the formatted TOML matches your team's style (e.g. Rust/Cargo vs Python/pyproject).

Is this TOML formatter free?

Yes, it's completely free with no signup and no usage limits. Use it as often as you like for personal or commercial projects.