Free JSON to TOML Converter

TOML is a minimal configuration language designed to be easy to read and write.

Yes — nested JSON objects are converted to TOML sections and arrays of objects become TOML array tables.

Yes, completely free. All processing happens in your browser.

Absolutely. The JSON to TOML Converter processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the JSON to TOML Converter is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the JSON to TOML Converter in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The JSON to TOML Converter works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

JSON and TOML both store structured key-value data, but they serve different purposes. JSON is a data-interchange format built for machines: it uses braces, quoted keys, and no comments, which makes it compact but harder to read and edit by hand. TOML (Tom's Obvious Minimal Language) is built for configuration files humans maintain. It allows comments, uses bare unquoted keys, and groups related settings under readable [table] headers, which is why Rust's Cargo.toml, Python's pyproject.toml, Hugo, and Deno all adopted it. TOML also has no null type and adds native dates, whereas JSON keeps everything as strings, numbers, booleans, arrays, objects, or null. This converter handles the structural translation between the two, mapping objects to tables and arrays of records to array-of-tables. Paste your JSON above to see clean TOML appear instantly.

TOML has no null type at all, so a JSON null cannot be represented directly the way it can in JSON or YAML. Rather than dropping the key silently, which would quietly change your data's shape, this converter writes a JSON null as an empty string (key = ""). That keeps the key present in the output so you can see it and decide what the value should actually be. This matters because a missing key and an explicit empty value mean different things to most config parsers. After converting, scan any keys you expect to hold real values and replace the empty strings with a proper default, a real value, or delete the line if the setting is genuinely optional. Paste your JSON above and the tool flags every null as an empty string for you to review.

When a JSON array contains objects rather than plain values, this converter emits it as a TOML array-of-tables, the idiomatic pattern for a list of records. Each element becomes its own repeated [[name]] block, with the object's fields written as key = value lines underneath. So a JSON array of two binary definitions produces two separate [[bin]] headers, each followed by its own name and path. This is different from a single nested object, which becomes one [table] header instead. Arrays that hold only strings, numbers, or booleans are left as ordinary inline arrays rather than being expanded into tables. The distinction is automatic and based on the contents of each array, so you do not need to flag anything. Paste a JSON config with a list of records above and watch the matching [[array-of-tables]] blocks build as you type.

A valid TOML document is fundamentally a set of key-value pairs at its root, so it must begin with named keys, not an anonymous value. A JSON object maps cleanly onto that structure, but a bare array like [1, 2, 3] or a lone primitive at the very top has no key to attach it to, which means there is no correct way to write it as standalone TOML. For that reason the converter requires the outermost JSON value to be an object and reports an error if you paste an array or primitive at the root. The fix is simple: wrap your data under a key, for example {"items": [1, 2, 3]}, and it converts cleanly into a named array. The live status badge shows Valid or Error as you type, so paste your JSON above and adjust the root if needed.

Both layouts are valid TOML and parse identically; the choice is about readability and version control. Inline keeps a primitive array on a single line, like ports = [80, 443], which is compact and ideal for short lists. One per line expands each element onto its own row inside the brackets, which reads far better for long arrays and produces cleaner diffs, since adding or removing one item changes a single line instead of rewriting the whole row. A good rule of thumb is inline for two or three short values and one-per-line for longer lists you expect to edit over time. This converter exposes both as a toggle, and you can also sort keys alphabetically for consistent, diff-friendly output. Pick the layout that matches your project's house style above, and the TOML regenerates instantly.