Free YAML to JSON Converter: No Sign-up, Nothing Uploaded
This free YAML to JSON converter turns indentation-based YAML into strict JSON. There is no sign-up or login, no watermark, and no upload: the file is converted in your browser and never leaves your device.
Use it when an API, a script or a validator wants JSON but your source is a YAML config. It is also a quick way to see exactly how a YAML file is parsed.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Drag your YAML or YML files onto the page or choose them with the file picker.
- Pick JSON as the target format.
- Check the options, then start the conversion.
- Download each JSON file, or take a batch as one ZIP.
Features
- Runs natively in your browser with no engine download.
- Accepts files ending in .yaml or .yml.
- Output is strict JSON that other tools can parse.
- Batch conversion of several files.
- No watermark and no account.
Supported formats
About the formats
What JSON cannot hold
YAML supports comments and features such as anchors and aliases. JSON has no comments, so any comments in your YAML will not appear in the result. Shared values referenced by anchors are written out in full where they are used.
Because YAML decides types from how a value looks, check that numbers, booleans and dates came out as you intended.
Privacy: how it works
- Your YAML 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.
- Deployment configs often hold credentials and internal addresses. Parsing runs in your tab, so none of that content leaves your machine.
Tips
- Fix indentation errors first, since YAML relies on consistent spaces to define structure.
- Expect comments to be dropped, and keep the YAML as your annotated source.
- Check values like yes, no and bare version numbers, which may be read as booleans or numbers.
- Use the result to validate your config against a JSON schema.
- Convert back with JSON to YAML if you want to confirm the data is unchanged.
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 YAML 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.