Spoold is a free, privacy-first developer toolbox. Paste into the Magic Box and it detects JSON, HTML, JWT, curl, OpenAPI, CSV, timestamps, and more—then suggests the best tool. You can also browse the full catalog by category. No sign-up is required.

Is Spoold free to use?

Yes. Core tools are free. Heavy work runs in your browser so your payloads are not processed on Spoold servers for formatting, decoding, and similar utilities.

Is my data safe with Spoold?

Tool processing for supported client-side utilities happens in your browser. Encrypted share links are designed so only people with the link can read the payload. Review the Privacy Policy for details on cookies, optional ads, and third-party services.

What tools are available?

Spoold ships 61+ tools including JSON formatter and diff, JSON Schema validation, YAML and TOML converters, HTML and Markdown preview, JWT decode and sign, OpenAPI/Swagger viewer with curl, GraphQL formatter, curl to code and curl compare, certificate viewer, CSV preview, regex tester, Mermaid, code editor, LLM token utilities, QR codes, and many encoding and text utilities.

Does Spoold show ads?

The site may display advertisements or sponsored placements to help keep the service free. House promotions highlight other Spoold tools. Ads do not change the fact that supported tools process your pasted content locally in the browser. You can read how to manage ad cookies and opt-outs in the Privacy Policy.

Can I use keyboard shortcuts?

Yes. Press Cmd or Ctrl+K to open tool search, use / from the homepage, and use per-tool shortcuts (shown in the UI) such as jj for JSON and hh for HTML where configured.

TOML Formatter & Validator Online — Format Cargo.toml, pyproject.toml

Guide: TOML Formatter & Validator

↑ Back to tool

What is this tool?

This TOML formatter and TOML validator runs in your browser. Paste TOML (Tom's Obvious, Minimal Language)—valid configs are pretty-printed on the right as you type; parse errors show in the status area. It uses a standard TOML parser; your text is not uploaded to a server. No sign-up.

Use it as an online TOML formatter for snippets, Cargo.toml, pyproject.toml, CI configs, and any file that must be valid TOML before you commit or share.

💡 Quick tip

Keep a copy of files that rely on comments—formatting rewrites TOML and comments are not preserved.

Why TOML?

TOML is a common choice for human-readable configuration: explicit tables, clear nesting, and less ambiguity than YAML for many teams. It appears in Rust (Cargo.toml), Python packaging (pyproject.toml), static sites, Netlify, Poetry, and more. A format TOML online workflow helps you catch typos and structure issues before they land in a repo.

Features

Live format & validate — Debounced parse; formatted output updates as you edit; invalid TOML surfaces a clear error message.
Monaco editor — Syntax-aware editing consistent with other Spoold formatters.
Copy output — One click to copy the formatted result.
History — Reopen recent sessions from the tool history panel when enabled.
Client-side — Parsing and formatting happen in your browser.

How to use

Open the tool — Paste TOML in the input panel or start from the sample.
Edit — Adjust keys, tables, and values; the formatted preview tracks your changes.
Check status — Green means valid; red means a parse error to fix in the source.
Copy — Use copy on the output panel when you are ready to paste elsewhere.

Use cases

Scenario	How this tool helps
Rust / Cargo	Normalize Cargo.toml layout and catch syntax mistakes.
Python packaging	Validate and pretty-print pyproject.toml sections.
CI & deploy configs	Quick-check TOML before pasting into pipelines or docs.
Teaching & snippets	Show clearly indented examples for blog posts or READMEs.

Best practices

Back up commented files — Formatting drops inline comments (see limitations).
Fix errors at the source — The tool highlights parse failures; correct the input, not the preview alone.
Very large files — The browser may slow down; consider splitting or using a local editor for huge monoliths.

JSON & TOML workflows

This page is TOML-only (format & validate). For JSON, use the JSON Formatter; for JSON ↔ YAML, use JSON ↔ YAML; for two-way JSON ↔ TOML, use JSON ↔ TOML.

Limitations

Formatting re-parses and stringifies TOML. Inline comments and whitespace outside string values are not preserved—keep a backup if comments matter. Very large files may feel slow in the browser.

FAQ

Is this TOML formatter free?

Yes. It runs client-side in your browser with no sign-up.

Does format preserve comments?

No. The formatter parses TOML to a data structure and writes it again, which drops comments. Keep a copy if you need annotations.

Is this a TOML linter for style rules?

It validates syntax and pretty-prints. It does not enforce project-specific naming or ordering rules like a dedicated linter might.

Can I convert TOML to JSON here?

Not on this page—only format and validate TOML. Use the JSON ↔ TOML converter for two-way conversion, or JSON Formatter for JSON-only work.

Does it work offline?

After the app loads, formatting runs in your browser without sending your text to Spoold servers.

Core: toml formatter, toml validator, format toml online, toml pretty print, toml beautifier, validate toml online, taplo format online alternative, TOML v1.0.0 syntax check.

Ecosystem: cargo toml format, rustfmt toml (workflow), pyproject toml validator, poetry.toml indent, hatch.toml format, uv tool toml, pdm.toml format, alacritty.yml vs toml (wrong file—use YAML tool).

Infra: netlify.toml format, wrangler.toml validate, telegraf.conf toml, containerd config toml, timescaledb toml snippets.

Convert: json to toml converter on Spoold, yaml vs toml for config. toml sort keys (manual) patterns.

Similar tools

Other Spoold utilities you might use alongside TOML:

Conclusion

Use this TOML formatter and validator to pretty-print and check config files in the browser. Pair it with JSON, JSON ↔ YAML, JSON ↔ TOML, or XML when your stack mixes formats.