TOML Validator

Validate TOML config file syntax and find errors instantly in your browser

Paste TOML on the left to validate...

What is TOML Validator?

The TOML Validator checks your TOML configuration file syntax for errors and reports them with exact line numbers. TOML (Tom's Obvious Minimal Language) is used in Rust projects (Cargo.toml), Python projects (pyproject.toml), Hugo static sites, and many other tools. A missing quote, duplicate key, or invalid value can silently break your build. This tool catches those errors instantly in your browser.

Why Use DevBench TOML Validator?

DevBench TOML Validator runs entirely in your browser — your data never leaves your device. No sign-up, no limits, no watermarks, completely free forever.

How to Use TOML Validator

  1. Paste your TOML content into the input textarea
  2. Errors appear instantly with line numbers
  3. Click Load Sample to see correct TOML syntax
  4. The stats cards show total lines, error count, and validation status
  5. Fix errors and re-paste to confirm the TOML is clean

Examples

  • Validate a Cargo.toml file for a Rust project
  • Check a pyproject.toml for Python packaging errors
  • Validate a Hugo config.toml before building a static site
  • Check a Gitea or Forgejo app.ini TOML config
  • Validate a custom TOML config file for a CLI application

Use Cases

  • Rust developers validating Cargo.toml before building
  • Python developers checking pyproject.toml syntax
  • Hugo static site developers validating config.toml
  • Anyone debugging TOML configuration file errors
  • DevOps engineers checking TOML-based tool configs
  • Students learning TOML syntax and structure
  • Teams reviewing TOML config files before deployment

Frequently Asked Questions

What is TOML?

TOML (Tom's Obvious Minimal Language) is a configuration file format using key = value pairs, [table] sections, and [[array of tables]]. It is used in Rust (Cargo.toml), Python (pyproject.toml), and many other tools.

What are the most common TOML errors?

Common TOML errors include: duplicate keys in the same table, missing values after the equals sign, unmatched quotes in string values, and unclosed array brackets.

Is my TOML sent to a server?

No. All validation runs entirely in your browser using JavaScript. Your TOML content never leaves your device.

What is the difference between TOML and YAML?

TOML uses explicit key = value syntax and is less sensitive to indentation than YAML. TOML is generally easier to write correctly for configuration files.

Does this validate TOML data types?

This tool validates TOML structure and syntax including key format and duplicate detection. Full data type validation for dates, floats, and integers may not catch all edge cases.