TOML Validator / Formatter
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What is a TOML Validator / Formatter?
A TOML validator helps you check whether TOML configuration files are syntactically valid.
A TOML formatter makes configuration files easier to read and inspect. This is useful for apps, tooling, build systems, and config files.
How to use the TOML Validator / Formatter
- Paste your TOML into the input field.
- Click Validate to check syntax.
- Click Format to normalize and reprint the TOML.
- Use TOML → JSON if you want to inspect the parsed structure.
Tips
- TOML is commonly used for configuration files.
- Keys, tables, arrays, booleans, and numbers must follow TOML syntax rules.
- Converting TOML to JSON is useful for debugging config structure.
- Formatting makes large config files much easier to review.
TOML checks before using a configuration file
Syntax validation should be followed by checks for table shape, value types, date semantics, and compatibility with the consuming library.
Tables and dotted keys
Check duplicate definitions, parent-child conflicts, arrays of tables, quoted keys, and unintended nesting from dotted names.
Value types
Confirm integers, floats, booleans, arrays, inline tables, multiline strings, and mixed-type restrictions match the application.
Dates and times
Distinguish local dates, local date-times, offset date-times, precision, and timezone assumptions before conversion.
Parser version
Load the file with the exact TOML implementation used by the application because feature and specification support can differ.
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