Free TOML to JSON Converter: No Sign-up, Files Never Uploaded
This free TOML to JSON converter runs entirely on your device. You do not need an account or a login, and your files are never uploaded, so they never leave your browser.
The file is parsed into a data tree and written out again as JSON.
This pair runs on code that is already in the page, so there is no extra engine to download.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Add your TOML files by dragging them onto the converter or by using the file picker.
- Check that JSON is the selected target format; it is already chosen on this page.
- Open the options if you want to change indentation, delimiter and root name, or keep the defaults.
- Press Convert and watch the progress shown for each file.
- Download each result, or take them all together as one ZIP when you converted several files.
Features
- Reads .toml and writes .json.
- Free, with no watermark added to the result.
- No sign-up and no login.
- Your files are never uploaded and never leave your device.
- Batch conversion with a ZIP download for several results.
- The input is recognised by its content, not only by its file name.
Supported formats
About the formats
About TOML
Tom’s Obvious Minimal Language: INI-like configuration with real data types.
Used by Cargo and Python’s pyproject.toml.
About JSON
JavaScript Object Notation: the usual format for web APIs.
Human-readable text; strict about quotes and commas.
TOML vs JSON
TOML does not support transparency, and JSON does not.
TOML files use the .toml extension and JSON files use .json, so the converted file gets a new name with the new extension.
Privacy: how it works
- Your TOML files stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
Tips
- Keep the original file; comments and key order are not always preserved between formats.
- Lists of records with the same fields convert most cleanly to tables.
- Validate the output with the tool that will read it.
- Check numbers and booleans in the result, since some formats store everything as text.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your TOML files are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow, and a very big batch may need to be split into smaller runs.
What is the difference between TOML and JSON?
TOML does not support transparency, and JSON does not. TOML files use the .toml extension and JSON files use .json, so the converted file gets a new name with the new extension.
Can I convert many TOML files at once?
Yes. Add as many files as your device can handle. Each one is converted on its own and you can download them one by one or as a single ZIP.
Will anything be lost when I convert TOML to JSON?
The converter keeps the content of the file. Check the result once, since small differences in metadata or colour handling can happen between formats.
Can I convert JSON back to TOML?
Yes. Open the JSON to TOML page and use the same steps. Converting back does not undo any loss from the first conversion.