TOML validator
Check TOML 1.1 syntax locally, including dates and duplicate keys. Download a safe diagnostic report or your accepted original configuration.
TOML 1.1 syntax, not application-schema validation or an older-version compatibility check. Up to 1,000,000 characters, 50,000 values and 64 nesting levels. Runs locally using smol-toml 1.9.1 with strict Temporal date handling. Paste text to process locally. Review the result before downloading. Results update as you type. Up to 1,000,000 characters.
Your result
How to use TOML validator
- Paste a TOML configuration.
- Review whether the syntax is accepted and any reported location.
- Download the report, or the unchanged TOML if it is accepted.
Useful next steps
Validate a complete TOML configuration
Paste a TOML configuration containing tables, arrays, strings, numbers or dates. The checker targets TOML 1.1 and accepts its additional constructs. A successful result is not proof of compatibility with an application that supports only TOML 1.0 or an older version.
Check dates and preserve the original text
The parser uses strict calendar validation and exact BigInt integer parsing. Successful validation returns the original text unchanged, including comments and numeric spelling. It does not convert your configuration to JSON or change its values.
Separate syntax from application settings
A syntax-valid configuration can still contain an unknown application option or incorrect value. This tool does not apply an application schema, resolve environment variables or test credentials. Error reports contain fixed messages and available line and column numbers, without including configuration lines or nearby secrets.