No upload, 100% local, no account

Data Converter

Convert between JSON, YAML and CSV. Everything stays in your browser.

How Data Converter works

Convert data between JSON, YAML, and CSV formats. Paste your source data, pick the target format, and get the result instantly. The CSV output follows RFC 4180: comma-delimited, double-quoted fields where needed, header row first.

Be aware of inherent format limitations: CSV cannot represent nested objects, deeply nested JSON will be flattened or may lose structure. YAML preserves types and nesting better than CSV, but converting back from CSV to JSON or YAML may not perfectly reconstruct the original hierarchy. For simple flat records, conversion is lossless; for complex nested data, review the output carefully.

Frequently asked questions

Are my files uploaded to a server?

No. Every operation runs inside your browser tab using JavaScript and WebAssembly. Your file is read into memory on your own device, processed there, and the result is offered as a local download. Nothing is transmitted to Sunasty or any third party. You can verify it yourself: open your browser DevTools, go to the Network tab, and watch, no request carries your file.

Will conversion always be lossless?

Not always. CSV is a flat format, it cannot represent nested objects or arrays. When converting nested JSON or YAML to CSV, the nesting is flattened or lost. Always review the output when working with complex data structures.

What CSV dialect does the converter use?

The converter follows RFC 4180: comma-delimited, double-quoted fields when necessary, header row on the first line. It does not support custom delimiters in this version.

Does it work offline?

Yes, once the page has loaded. Because the processing happens on your device, you can disconnect from the network and the tool keeps working. This is the clearest proof that your data never leaves your machine.

Is it free? Do I need an account?

It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.