TOML Validator
This TOML validator checks a TOML file (Cargo.toml, pyproject.toml, config) against TOML 1.0, with the line of any error.
Waiting for input
What you get
- Validate TOML online against TOML 1.0: a TOML syntax checker for Cargo.toml, pyproject.toml and config files.
- Duplicate keys, redefined tables and invalid values are errors, each with its line.
- Valid TOML is shown normalized, checked to hold the same data with the same types: 64-bit integers, floats, dates and times.
- A TOML linter for configs, and a pyproject.toml validator for Python projects: errors name the line.
- Private and free: everything runs in your browser, nothing is uploaded, and there is no sign-up.
How each result is checked
- Parsed strictly as TOML 1.0: duplicate keys, redefined tables and bad values are errors with their line.
- Valid TOML is shown normalized, and that output is checked to hold the same data with the same TOML types: integers (including 64-bit), floats, dates, times, inf and nan.
What can't convert exactly
- The normalized output leaves out comments, since they are not data.
- Floats are written with a decimal point (1.0 stays a float) and times with milliseconds (07:32:00.000); the values are the same.
Questions
Is my data uploaded?
No. Everything runs in your browser, in a background worker. Nothing is sent to a server.
Which TOML version does it validate against?
TOML 1.0, the version Cargo, pip, Poetry and most current tools read.
Why did my duplicate key pass in another tool?
Some TOML readers keep the last value. TOML 1.0 forbids defining a key or table twice, so this validator reports it with the line.
How do I use the TOML Validator online?
Paste your input or open a file on the left. The result appears on the right as you type, already checked; copy or download it. Nothing is uploaded: the TOML Validator runs in your browser.