Developer Tools

TOML Formatter

Paste TOML configuration and validate its syntax instantly. Catches common errors like duplicate keys, invalid values, and malformed tables, with exact line numbers reported.

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toml TOML
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Features

  • Validates TOML syntax with precise error locations
  • Identifies duplicate key errors
  • Checks table and array-of-tables structure
  • Formats TOML with consistent spacing
  • Browser-only. No upload

How to use it

  1. Paste your TOML content into the input panel.
  2. Validation runs automatically.
  3. If valid, formatted TOML appears in the output.
  4. If invalid, the error message shows the line and nature of the problem.

Use cases

  • Validating Cargo.toml for Rust projects
  • Checking Hugo or Zola config.toml files
  • Debugging Pyproject.toml configuration
  • Verifying CI/CD pipeline TOML config

Limitations

  • Very complex multi-document TOML files may need to be split before pasting.
See also

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Questions & answers

Frequently asked

What version of TOML is supported?

TOML v1.0 specification is used, including inline tables, arrays of tables, and all scalar types.