JSON to TOML converter
Drop in a JSON and get a TOML back. TOML is the usual choice for rust crate manifests in Cargo.toml. Worth knowing: a TOML will not open in a browser tab, so it is a file for software rather than for the web. Your file never leaves your computer.
Need the other direction? Convert TOML to JSON
How to convert JSON to TOML
- 1 Drop your JSON .json file onto the page, or click to browse for it.
- 2 Check the options. Nothing is thrown away on the way to TOML, so there is no quality dial to set.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the TOML, or add more files and do the whole set in one go.
Why convert JSON to TOML
- Unambiguous rules, so two programs always agree on what it means.
- Dates and times are first-class values rather than strings.
- Settings files a person is expected to edit by hand.
- JSON: very large numbers can quietly lose precision.
JSON compared with TOML
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | JSON | TOML |
|---|---|---|
| File extension | .json | .toml |
| Colour depth | UTF-8 text, six value types, no comments or trailing commas | UTF-8 key-value text with tables, arrays and native date types |
| Browser support | Every browser | No browser support |
| Introduced | 2001 | 2013 |
| Developed by | Douglas Crockford | Tom Preston-Werner |
Quality and what changes
Both sides are lossless, so every pixel survives the trip intact and converting back returns the same image. What changes is the size and what the file can carry: TOML stores the data without compression, so expect a much larger file.
- Browsers will not display a TOML, so it downloads rather than opening in a tab.
- One TOML limitation to keep in mind: deeply nested settings get awkward and long-winded.
Questions about JSON to TOML
Can I open a TOML in a browser?
No. No mainstream browser renders TOML natively, so it will download rather than display. That is fine when the file is heading into desktop software or an archive, and a problem if it is going on a web page.
Is my JSON file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your JSON is read straight from your own disk, converted on your machine and handed back as a TOML. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several JSON files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate TOML downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.