A JSON workspace that runs in your browser

What it does

Highlights

• Format, validate, repair and minify from one toolbar
• Side-by-side diff with synced scrolling and change navigation
• Collapsible tree view for deeply nested documents
• Two-way JSON and YAML conversion
• Errors carry a line, a column and a click that jumps there
• Undo works after every tool, including Format and Minify

Frequently asked questions

Is my JSON uploaded anywhere?

No. There is no server component. Everything runs in the browser tab and is gone when you close it.

How large a document can it handle?

Multi-megabyte files are fine. Parsing is synchronous, so a very large document pauses the tab for a moment while a tool runs, but typing and scrolling stay smooth because neither re-renders the document.

Which JSON dialect is accepted?

Strict RFC 8259, using the browser's own parser — the same rules your application will apply. Comments and trailing commas are rejected; Repair cleans those up.

Does undo still work after running a tool?

Yes. Format, Minify, Repair, Paste and Upload all write through the browser's native undo stack, so Ctrl+Z (Cmd+Z) steps back through them like ordinary edits.

Do I need an account?

No. Nothing is stored between visits except your light or dark theme preference.

Related tools

• JSON FormatterTwo-space indentation, key order untouched, undo still works.
• JSON ValidatorLine, column and reason for the first thing a parser rejects.
• JSON RepairTrailing commas, single quotes and bare keys, fixed and re-parsed.
• JSON MinifierWhitespace removed, savings measured in real UTF-8 bytes.
• JSON DiffStructural comparison with change-to-change navigation.
• JSON to YAMLBlock-style YAML, two-space indent, keys in their original order.
• YAML to JSONFormatted JSON out, with real errors when YAML has no equivalent.