TOML to JSON Converter
FileFlip converts TOML to JSON entirely inside your browser, using the text engine compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a TOML file to JSON?#
- Drop your TOML file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to JSON and the conversion starts on its own. FileFlip downloads nothing at all, because everything it needs is already built into your browser, then runs the text engine on your own machine.
- Save the JSON file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting TOML to JSON lose quality?#
No. Converting TOML to JSON writes the data out again without discarding any of it, so nothing that was in the TOML file is lost on the way. What changes is the size of the file, not what is inside it.
Is it safe to convert TOML files online?#
Yes, because nothing is uploaded. FileFlip converts TOML files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What TOML to JSON actually does to the file#
Converting TOML to JSON runs on the text engine, downloads nothing at all, because everything it needs is already built into your browser, writes the data out again without discarding any of it, keeps value types, and drops comments.
| Engine | the text engine |
|---|---|
| Conversion path | One step: TOML → JSON |
| Downloaded to your browser | Nothing. Your browser already has everything this conversion needs |
| Quality | Lossless |
| You get back | One file |
| Where it runs | On the page's own thread, so a very large file will make the tab wait |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Comments | Dropped | The target format has nowhere to put it. |
| Value types | Kept | Carried through into the converted file. |
Worth knowing before you start:
- this conversion runs on the page's own thread, so a large file will freeze the tab while it works
What is a TOML file?#
A TOML file holds configuration as key-value pairs grouped into tables, with native types for strings, integers, floats, booleans, arrays and dates.
Pick TOML for configuration files a person writes and re-reads by hand, where explicit types and unambiguous structure matter more than deep nesting.
Convert TOML to JSON or YAML when the data needs to nest more than a couple of levels deep, or when the tool consuming it doesn't have a TOML parser.
What is a JSON file?#
A JSON file holds data as nested objects and arrays built from strings, numbers, booleans and null, and nothing else, written in the syntax JavaScript uses for object literals.
Reach for JSON when data moves between programs and nobody needs to hand-edit it, since every language parses it the same way.
Convert JSON to YAML or TOML when a person needs to edit the file directly and wants comments, or to CSV when a spreadsheet or a script expecting rows is the destination.
TOML to JSON questions people ask#
Why can't I convert a TOML file to a JSON array?
A TOML document always starts as a table of key-value pairs, so a file that only needs to model a top-level list, like a plain array of strings, doesn't fit TOML's grammar at all. Converting a JSON array to TOML has to wrap the array under a key, like items = [...], because TOML has no bare top-level list.
Does TOML support comments?
Yes. TOML comments start with a hash character and run to the end of the line, the same as YAML and Python. That's one of the reasons TOML was picked for Cargo.toml and pyproject.toml over JSON, which has no comment syntax at all.
What happens to TOML's dates when converting to JSON?
TOML has a native date-time type with its own syntax, and JSON has none, so converting to JSON turns every TOML date into a plain string. Which string format it becomes depends on the converter, since JSON doesn't specify one either.
Why doesn't JSON support comments?
JSON has no comment syntax by design. Douglas Crockford, who specified JSON, has said he removed comments deliberately after seeing people use them to hold parsing directives that broke interoperability between tools. A config file written in JSON that needs to explain itself either adds a plain key like _comment by convention, or moves to a JSON superset like JSON5 or JSONC, which aren't plain JSON.