Question 1

Is JSON OS free to use?

Accepted Answer

Yes. JSON OS is free, requires no account, and works entirely in your browser.

Question 2

Is my JSON data uploaded to a server?

Accepted Answer

No. All parsing, validation, formatting, and storage happen locally in your browser. Documents persist in your browser's IndexedDB and never leave your device unless you explicitly export them.

Question 3

What can the Repair feature fix?

Accepted Answer

Repair handles comments (// /* */ #), smart quotes, single-quoted strings, unquoted object keys, trailing commas, missing commas, hex/octal/binary numbers, Python literals (True, False, None), undefined and NaN, unclosed brackets, and stray top-level values. After running, a banner lists each fix that was applied.

Question 4

Can I compare two JSON documents side by side?

Accepted Answer

Yes. Click the ⇄ Compare button or press Cmd+Shift+C. Pick a peer document, choose tree or text view, and the workspace switches to two linked columns with synced scroll and color-coded differences (added, removed, changed, moved). Ignore rules let you skip specific paths, treat null as missing, ignore string case, or trim whitespace.

Question 5

Can I validate JSON against a schema?

Accepted Answer

Yes. Open the side panel, pick the Schema tab, and paste a JSON Schema. The active document is continuously validated using Ajv with formats. Errors appear inline with their instance paths.

Question 6

Does it work offline?

Accepted Answer

After the first load, the app and your saved documents work without a network. JSON parsing runs in a Web Worker; everything is stored in IndexedDB on your device.