TOML to JSON Converter & TOML Validator
Convert TOML 1.0 to JSON or YAML and validate it: tables, arrays of tables, dotted keys, dates, hex and big integers, with line and column for every error.
Dates and times are written as text exactly as in the TOML (JSON has no date type). Use "Typed JSON" to keep which kind of date each one is.
Floats are written with a decimal point (72.0 stays 72.0) so they stay floats.
TOML is the configuration format of Cargo.toml, pyproject.toml, Hugo, Netlify and many other tools. This converter parses TOML 1.0 exactly as the specification describes and turns it into JSON or YAML, so you can feed the data to a program, compare two configurations or check what a file really means. It doubles as a validator: any mistake — a duplicate key, a table defined twice, a missing quote — is reported with its line and column.
How to use this tool
- Paste the TOML document.
- Choose JSON, YAML or typed JSON.
- Pick the indentation and how inf and nan are written in JSON.
- Copy the result, or fix the error at the line and column shown.
Formula
[table] → object · [[array]] → array of objects · a.b.c = v → nested objects · dates → text as written
All of TOML 1.0 is supported: bare, quoted and dotted keys, basic and literal strings (single and multi-line, with line-ending backslashes), integers in decimal, hex, octal and binary with underscores, floats with exponents, inf and nan, booleans, offset and local date-times, local dates and times, arrays and inline tables. The rules for defining tables follow the specification: a table can be defined only once, dotted keys cannot add to a table defined by a header, inline tables are closed. Integers are 64-bit and keep every digit; key order is kept.
Example
The sample is the example from toml.io. [owner] becomes an object with name and dob, where dob stays 1979-05-27T07:32:00-08:00; ports becomes [8000, 8001, 8002]; the inline table temp_targets becomes {"cpu": 79.5, "case": 72.0} — 72.0 keeps its decimal point; [servers.alpha] and [servers.beta] become two objects inside servers. In total 16 values are converted (each array item counts).
Frequently asked questions
Why are dates strings in the JSON?
JSON has no date type, so they are written as text, exactly as in the TOML. Choose Typed JSON to see whether each one is an offset date-time, a local date-time, a date or a time.
What does "table defined more than once" mean?
In TOML each [table] may appear only once, and a table created with dotted keys (apple.color = "red") cannot be opened again with [fruit.apple]. Merge the two blocks into one.
Does it support TOML 1.1?
It follows TOML 1.0.0. Features new in 1.1, such as inline tables over several lines or times without seconds, are reported as errors.
Is my file uploaded?
No. Parsing happens in your browser.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/toml-to-json-tool/
Cite or embed this tool
kakaoCalc. (2026, November 8). TOML to JSON Converter & TOML Validator. https://kakao.mobile/tools/toml-to-json-tool/
“TOML to JSON Converter & TOML Validator.” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/toml-to-json-tool/.
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