TOML to JSON Converter

TOML is the configuration format of Cargo.toml, pyproject.toml, Hugo and many other tools. The document is parsed with smol-toml, a parser for TOML 1.0. A table [server] becomes a JSON object, dotted keys such as a.b = 1 become nested objects, an array of tables [[workers]] becomes an array of objects, and an inline table { min = 2, max = 20 } an object. Comments are dropped because JSON cannot hold them.

JSON has no date type, so the four kinds of TOML dates are written as strings in RFC 3339 form: an offset date-time stays as written ("1979-05-27T00:32:00-07:00"), a local date-time has no offset ("1979-05-27T07:32:00"), a local date is "1979-05-27" and a local time "07:32:00". Fractions of a second are kept to the millisecond. Integers beyond 2⁵³ are written in full, although JavaScript rounds them when it reads the JSON, and inf and nan, which JSON does not have, are written as the strings "inf", "-inf" and "nan".

Invalid TOML gives an error with the line and column, for example a key that is defined twice, a table that is declared again, a string that is not closed or a number with a leading zero. That makes the tool a quick validator before you commit a configuration file. TOML keeps tables after the plain values of their parent, so the order of keys in the JSON follows the TOML document. The conversion runs in your browser.